Roles of neutrophils in the regulation of the extent of human inflammation through delivery of IL-1 and clearance of chemokines

This study examined the establishment of neutrophilic inflammation in humans. We tested the hypotheses that neutrophil recruitment was associated with local CXCL8 production and that neutrophils themselves might contribute to the regulation of the size of the inflammatory response. Humans were challenged i.d. with endotoxin. Biopsies of these sites were examined for cytokine production and leukocyte recruitment by qPCR and IHC. Additional in vitro models of inflammation examined the ability of neutrophils to produce and sequester cytokines relevant to neutrophilic inflammation. i.d. challenge with 15 ng of a TLR4-selective endotoxin caused a local inflammatory response, in which 1% of the total biopsy area stained positive for neutrophils at 6 h, correlating with 100-fold up-regulation in local CXCL8 mRNA generation. Neutrophils themselves were the major source of the early cytokine IL-1β. In vitro, neutrophils mediated CXCL8 but not IL-1β clearance (>90% clearance of ≤2 nM CXCL8 over 24 h). CXCL8 clearance was at least partially receptor-dependent and modified by inflammatory context, preserved in models of viral infection but reduced in models of bacterial infection. In conclusion, in a human inflammatory model, neutrophils are rapidly recruited and may regulate the size and outcome of the inflammatory response through the uptake and release of cytokines and chemokines in patterns dependent on the underlying inflammatory stimulus

Pig α₁-Acid Glycoprotein: Characterization and First Description in Any Species as a Negative Acute Phase Protein.

The serum protein α1-acid glycoprotein (AGP), also known as orosomucoid, is generally described as an archetypical positive acute phase protein. Here, porcine AGP was identified, purified and characterized from pooled pig serum. It was found to circulate as a single chain glycoprotein having an apparent molecular weight of 43 kDa by SDS-PAGE under reducing conditions, of which approximately 17 kDa were accounted for by N-bound oligosaccharides. Those data correspond well with the properties of the protein predicted from the single porcine AGP gene (ORM1, Q29014 (UniProt)), containing 5 putative glycosylation sites. A monoclonal antibody (MAb) was produced and shown to quantitatively and specifically react with all microheterogenous forms of pig AGP as analyzed by 2-D electrophoresis. This MAb was used to develop an immunoassay (ELISA) for quantification of AGP in pig serum samples. The adult serum concentrations of pig AGP were in the range of 1-3 mg/ml in a number of conventional pig breeds while it was lower in Göttingen and Ossabaw minipigs (in the 0.3 to 0.6 mg/ml range) and higher in young (2-5 days old) conventional pigs (mean: 6.6 mg/ml). Surprisingly, pig AGP was found to behave as a negative acute phase protein during a range of experimental infections and aseptic inflammation with significant decreases in serum concentration and in hepatic ORM1 expression during the acute phase response. To our knowledge this is the first description in any species of AGP being a negative acute phase protein

The European Hematology Association Roadmap for European Hematology Research. A Consensus Document

Abstract The European Hematology Association (EHA) Roadmap for European Hematology Research highlights major achievements in diagnosis and treatment of blood disorders and identifies the greatest unmet clinical and scientific needs in those areas to enable better funded, more focused European hematology research. Initiated by the EHA, around 300 experts contributed to the consensus document, which will help European policy makers, research funders, research organizations, researchers, and patient groups make better informed decisions on hematology research. It also aims to raise public awareness of the burden of blood disorders on European society, which purely in economic terms is estimated at Euro 23 billion per year, a level of cost that is not matched in current European hematology research funding. In recent decades, hematology research has improved our fundamental understanding of the biology of blood disorders, and has improved diagnostics and treatments, sometimes in revolutionary ways. This progress highlights the potential of focused basic research programs such as this EHA Roadmap. The EHA Roadmap identifies nine sections in hematology: normal hematopoiesis, malignant lymphoid and myeloid diseases, anemias and related diseases, platelet disorders, blood coagulation and hemostatic disorders, transfusion medicine, infections in hematology, and hematopoietic stem cell transplantation. These sections span 60 smaller groups of diseases or disorders. The EHA Roadmap identifies priorities and needs across the field of hematology, including those to develop targeted therapies based on genomic profiling and chemical biology, to eradicate minimal residual malignant disease, and to develop cellular immunotherapies, combination treatments, gene therapies, hematopoietic stem cell treatments, and treatments that are better tolerated by elderly patients. Received December 15, 2015. Accepted January 27, 2016. Copyright © 2016, Ferrata Storti Foundatio

Identification of two distinct pathways of human myelopoiesis

Human myelopoiesis has been proposed to occur through oligopotent common myeloid progenitor (CMP) and lymphoid-primed multipotent progenitor (LMPP) populations. However, other studies have proposed direct commitment of multipotent cells to unilineage fates, without specific intermediary lineage cosegregation patterns. We here show that distinct human myeloid progenitor populations generate the neutrophil/monocyte and mast cell/basophil/eosinophil lineages as previously shown in mouse. Moreover, we find that neutrophil/monocyte potential selectively cosegregates with lymphoid lineage and mast cell/basophil/eosinophil potentials with megakaryocyte/erythroid potential early during lineage commitment. Furthermore, after this initial commitment step, mast cell/basophil/eosinophil and megakaryocyte/erythroid potentials colocalize at the single-cell level in restricted oligopotent progenitors. These results show that human myeloid lineages are generated through two distinct cellular pathways defined by complementary oligopotent cell populations

A conceptual framework for the identification of candidate drugs and drug targets in acute promyelocytic leukemia

Chromosomal translocations of transcription factors generating fusion proteins with aberrant transcriptional activity are common in acute leukemia. In acute promyelocytic leukemia (APL), the promyelocytic leukemia-retinoic-acid receptor alpha (PML-RARA) fusion protein, which emerges as a consequence of the t(15;17) translocation, acts as a transcriptional repressor that blocks neutrophil differentiation at the promyelocyte (PM) stage. In this study, we used publicly available microarray data sets and identified signatures of genes dysregulated in APL by comparison of gene expression profiles of APL cells and normal PMs representing the same stage of differentiation. We next subjected our identified APL signatures of dysregulated genes to a series of computational analyses leading to (i) the finding that APL cells show stem cell properties with respect to gene expression and transcriptional regulation, and (ii) the identification of candidate drugs and drug targets for therapeutic interventions. Significantly, our study provides a conceptual framework that can be applied to any subtype of AML and cancer in general to uncover novel information from published microarray data sets at low cost. In a broader perspective, our study provides strong evidence that genomic strategies might be used in a clinical setting to prospectively identify candidate drugs that subsequently are validated in vitro to define the most effective drug combination for individual cancer patients on a rational basis. Leukemia (2010) 24, 1265-1275; doi:10.1038/leu.2010.95; published online 27 May 201

NMD is essential for hematopoietic stem and progenitor cells and for eliminating by-products of programmed DNA rearrangements.

Nonsense-mediated mRNA decay (NMD) is a post-transcriptional surveillance process that eliminates mRNAs containing premature termination codons (PTCs). NMD has been hypothesized to impact on several aspects of cellular function; however, its importance in the context of a mammalian organism has not been addressed in detail. Here we use mouse genetics to demonstrate that hematopoietic-specific deletion of Upf2, a core NMD factor, led to the rapid, complete, and lasting cell-autonomous extinction of all hematopoietic stem and progenitor populations. In contrast, more differentiated cells were only mildly affected in Upf2-null mice, suggesting that NMD is mainly essential for proliferating cells. Furthermore, we show that UPF2 loss resulted in the accumulation of nonproductive rearrangement by-products from the Tcrb locus and that this, as opposed to the general loss of NMD, was particularly detrimental to developing T-cells. At the molecular level, gene expression analysis showed that Upf2 deletion led to a profound skewing toward up-regulated mRNAs, highly enriched in transcripts derived from processed pseudogenes, and that NMD impacts on regulated alternative splicing events. Collectively, our data demonstrate a unique requirement of NMD for organismal survival

Mutation of C/EBPalpha predisposes to the development of myeloid leukemia in a retroviral insertional mutagenesis screen.

The CCAAT enhancer binding protein alpha (C/EBPalpha) is an important myeloid tumor suppressor that is frequently mutated in human acute myeloid leukemia (AML). We have previously shown that mice homozygous for the E2F repression-deficient Cebpa(BRM2) allele develop nonfatal AML with long latency and incomplete penetrance, suggesting that accumulation of secondary mutations is necessary for disease progression. Here, we use SRS19-6-driven retroviral insertional mutagenesis to compare the phenotypes of leukemias arising in Cebpa(+/+), Cebpa(+/BRM2), and Cebpa(BRM2/BRM2) mice, with respect to disease type, latency of tumor development, and identity of the retroviral insertion sites (RISs). Both Cebpa(+/BRM2) and Cebpa(BRM2/BRM2) mice preferentially develop myeloid leukemias, but with differing latencies, thereby demonstrating the importance of gene dosage. Determination of RISs led to the identification of several novel candidate oncogenes, some of which may collaborate specifically with the E2F repression-deficient allele of Cebpa. Finally, we used an in silico pathway analysis approach to extract additional information from single RISs, leading to the identification of signaling pathways which were preferentially deregulated in a disease- and/or genotype-specific manner