Mutant CEBPA directly drives the expression of the targetable tumor-promoting factor CD73 in AML

The key myeloid transcription factor (TF), CEBPA, is frequently mutated in acute myeloid leukemia (AML), but the direct molecular effects of this leukemic driver mutation remain elusive. To investigate mutant AML, we performed microscale, in vivo chromatin immunoprecipitation sequencing and identified a set of aberrantly activated enhancers, exclusively occupied by the leukemia-associated CEBPA-p30 isoform. Comparing gene expression changes in human mutant AML and the corresponding mouse model, we identified , encoding CD73, as a cross-species AML gene with an upstream leukemic enhancer physically and functionally linked to the gene. Increased expression of CD73, mediated by the CEBPA-p30 isoform, sustained leukemic growth via the CD73/A2AR axis. Notably, targeting of this pathway enhanced survival of AML-transplanted mice. Our data thus indicate a first-in-class link between a cancer driver mutation in a TF and a druggable, direct transcriptional target

HemaExplorer: a database of mRNA expression profiles in normal and malignant haematopoiesis

The HemaExplorer (http://servers.binf.ku.dk/hemaexplorer) is a curated database of processed mRNA Gene expression profiles (GEPs) that provides an easy display of gene expression in haematopoietic cells. HemaExplorer contains GEPs derived from mouse/human haematopoietic stem and progenitor cells as well as from more differentiated cell types. Moreover, data from distinct subtypes of human acute myeloid leukemia is included in the database allowing researchers to directly compare gene expression of leukemic cells with those of their closest normal counterpart. Normalization and batch correction lead to full integrity of the data in the database. The HemaExplorer has comprehensive visualization interface that can make it useful as a daily tool for biologists and cancer researchers to assess the expression patterns of genes encountered in research or literature. HemaExplorer is relevant for all research within the fields of leukemia, immunology, cell differentiation and the biology of the haematopoietic system

The small and large intestine contain related mesenchymal subsets that derive from embryonic Gli1+ precursors

The intestinal lamina propria contains a diverse network of fibroblasts that provide key support functions to cells within their local environment. Despite this, our understanding of the diversity, location and ontogeny of fibroblasts within and along the length of the intestine remains incomplete. Here we show that the small and large intestinal lamina propria contain similar fibroblast subsets that locate in specific anatomical niches. Nevertheless, we find that the transcriptional profile of similar fibroblast subsets differs markedly between the small intestine and colon suggesting region specific functions. We perform in vivo transplantation and lineage-tracing experiments to demonstrate that adult intestinal fibroblast subsets, smooth muscle cells and pericytes derive from Gli1-expressing precursors present in embryonic day 12.5 intestine. Trajectory analysis of single cell RNA-seq datasets of E12.5 and adult mesenchymal cells suggest that adult smooth muscle cells and fibroblasts derive from distinct embryonic intermediates and that adult fibroblast subsets develop in a linear trajectory from CD81+ fibroblasts. Finally, we provide evidence that colonic subepithelial PDGFRαhi fibroblasts comprise several functionally distinct populations that originate from an Fgfr2-expressing fibroblast intermediate. Our results provide insights into intestinal stromal cell diversity, location, function, and ontogeny, with implications for intestinal development and homeostasis

Joint Venture i Kina - en hoppfull problematik

Syfte: Studiens syfte är att identifiera de faktorer som är viktiga för svenska företag att ha i åtanke för att få ett fungerande samarbete, i form av ett joint venture, på den reglerade kinesiska marknaden. Metod: Studien bygger på tre kvalitativa fallstudier gjorda på svenska företag etablerade i Kina. Respondenterna består av dels representanter från fallföretagen och dels konsulter med inriktning på affärsetablering i Kina. Genom hela studien används följande tre punkter för att få en sammanhängande struktur: val av samarbetspartner, struktur på samarbetet samt ledningsfilosofi. De tre ovanstående punkterna underbyggs alla av varsin teori, som är utgångspunkten för studiens analys. Slutsatser: Studien har resulterat i ett bidrag till hur företag som bildar ett joint venture ska gå tillväga för att i bästa möjliga mån kunna nå ett fungerande samarbete. Det görs en koppling mellan de olika teorier som använts och hur de samverkar. Slutligen sammanställs de viktigaste faktorerna att beakta vid etablering av ett joint venture i Kina

The IgD-binding domain of the Moraxella IgD-binding protein MID (MID962-1200) activates human B cells in the presence of T cell cytokines.

Moraxella catarrhalis immunoglobulin D (IgD)-binding protein (MID) is an outer membrane protein with specific affinity for soluble and cell-bound human IgD. Here, we demonstrate that mutated M. catarrhalis strains devoid of MID show a 75% decreased activation of human B cells as compared with wild-type bacteria. In contrast to MID-expressing Moraxella, the MID-deficient Moraxella mutants did not bind to human CD19(+) IgD(+) B cells. The smallest MID fragment with preserved IgD-binding capacity comprises 238 amino acids (MID962-1200). To prove the specificity of MID962-1200 for IgD, a Chinese hamster ovary (CHO) cell line expressing membrane-anchored human IgD was manufactured. MID962-1200 bound strongly to the recombinant IgD on CHO cells. Moreover, MID962-1200 stimulated peripheral blood lymphocyte (PBL) proliferation 5- and 15-fold at 0.1 and 1.0 mu g/ml, respectively. This activation could be blocked completely by antibodies directed against the CD40 ligand (CD154). MID962-1200 also activated purified B cells in the presence of interleukin (IL)-2 or IL-4. An increased IL-6 production was seen after stimulation with MID962-1200, as revealed by a human cytokine protein array. MID962-1200 fused to green fluorescent protein (GFP) bound to human B cells and activated PBL to the same degree as MID962-1200 Taken together, MID is the only IgD-binding protein in Moraxella. Furthermore, the novel T cell-independent antigen MID962-1200 may, together with MID962-1200-GFP, be considered as promising reagents in the study of IgD-dependent B cell activation

Moraxella catarrhalis-dependent tonsillar B cell activation does not lead to apoptosis but to vigorous proliferation resulting in nonspecific IgM production.

The respiratory pathogen Moraxella catarrhalis has a high affinity for human IgD and is mitogenic for peripheral blood B lymphocytes. Moraxella IgD-binding protein, which is a multifunctional outer membrane protein with adhesive properties, is responsible for the interaction. Previous experiments with the Ig-binding B cell superantigens protein A and protein L from Staphylococcus aureus and Peptostreptococcus magnus, respectively, have suggested that nonimmune BCR cross-linking induces B cell apoptosis through the intrinsic pathway. The goal of this study was to characterize early and late B cell events in the presence of M. catarrhalis in comparison with S. aureus. Despite an increased phosphatidyl serine translocation as revealed by Annexin V binding in flow cytometry analyses, neither M. catarrhalis nor S. aureus induced activation-associated apoptotic cell death in purified human tonsillar B cells. In contrast, a vigorous B cell proliferation, as quantified using thymidine incorporation and CFSE staining, was observed. An increased expression of an array of surface proteins (i.e., CD19, CD21, CD40, CD45, CD54, CD69, CD86, CD95, and HLA-DR) and IgM production was found upon activation with M. catarrhalis. In conclusion, M. catarrhalis-dependent B cell activation does not result in apoptosis but in cell division and nonspecific IgM synthesis, suggesting that the bacterial interaction with tonsillar B cells serves to redirect the early adaptive immune response

Effects of NOD-like receptors in human B lymphocytes and crosstalk between NOD1/NOD2 and Toll-like receptors.

NLRs are recently discovered PRRs detecting substructures of peptidoglycans and triggering innate immunity. NLRs are expressed in several cell types, but the presence in human B lymphocytes is still unknown. This study aimed to investigate expression and function of NLRs in human B lymphocytes. B cells were isolated and analyzed for mRNA and protein expression. The functional responsiveness of NOD1 and NOD2 was investigated upon stimulation with the cognate ligands, with or without stimulation via IgM/IgD/CD40 and/or selected TLR agonists. A differential expression of NLRs was demonstrated in blood-derived and tonsillar B cells, whereas no variations were found among naive, germinal center, or memory B cells. Stimulation with the ligands alone did not induce B cell activation. However, upon concomitant BCR triggering, an increase in proliferation was seen, together with an induction of cell surface markers (CD27, CD69, CD71, CD80, CD86, and CD95) and prolonged survival. Peripheral B cells were activated by NOD1 and NOD2 ligands, whereas tonsil-derived B cells responded solely to NOD1. In contrast, costimulation with CD40L failed to induce activation. Additionally, it was found that NLR ligands could enhance TLR-induced proliferation of B cells. The present study demonstrates expression of functional NLRs in human B cells. We show that NOD1 and NOD2 have the ability to augment the BCR-induced activation independently of physical T cell help. Hence, NLRs represent a new pathway for B cell activation and a potentially important system of a host defense role against bacterial infections