Microglia colonize the brain parenchyma at early stages of development and accumulate in specific regions where they actively participate in cell death, angiogenesis, neurogenesis and synapse elimination. A recurring feature of embryonic microglial distribution is their association with developing axon tracts which, together with in vitro data, supports the idea of a physiological role for microglia in neurite development. Yet the demonstration of this role of microglia is still lacking. Here, we have studied the consequences of microglial dysfunction on the formation of the corpus callosum, the largest connective structure in the mammalian brain, which shows consistent microglial accumulation during development. We studied two models of microglial dysfunction: the loss-of-function of DAP12, a key microglial-specific signaling molecule, and a model of maternal inflammation by peritoneal injection of LPS at E15.5. We performed transcriptional profiling of maternally inflamed and Dap12-mutant microglia at E17.5. We found that both treatments principally down-regulated genes involved in nervous system development and function, particularly in neurite formation. We then analyzed the functional consequences of these microglial dysfunctions on the formation of the corpus callosum. We also took advantage of the Pu.1-/- mouse line, which is devoid of microglia. We now show that all three models of altered microglial activity resulted in the same defasciculation phenotype. Our study demonstrates that microglia are actively involved in the fasciculation of corpus callosum axons.
Microglia shape corpus callosum axon tract fasciculation: functional impact of prenatal inflammation.
Sex, Specimen part, Treatment
View SamplesAbstract Two major dendritic cell (DC) subsets have been described in the islets of mice: The immunogenic CD8-CD11b+ DCs and the tolerogenic CD8+CD103+ DCs. We have recently reported on reduced numbers of the minor population of tolerogenic CD8+CD103+ DCs in the pancreas of 5 week old pre-diabetic non-obese diabetic (NOD) mice. Aim: To analyze also the larger subset of CD11c+CD8- DCs isolated from the pancreas of pre-diabetic NOD mice 1) for maturation and tolerance inducing molecules found abnormally expressed on CD8+CD103+ DCs, and 2) for genome-wide gene expression to further elucidate abnormalities in underlying gene expression networks. Methods: CD11c+CD8- DCs were isolated from 5 week old C57BL/6 and NOD pancreas. Expression of cell surface markers including CD86, CCR5, CD11b, CD103, Clec9a, CD24 and CD200R3 were measured by FACS. Genome-wide gene expression by microarray was assessed during the steady state and after in vitro LPS stimulation. Results: The steady state pancreatic CD11c+ CD8- DCs during the pre-diabetic stage showed: 1) A reduced expression of several gene networks important for the prime functions of the cell, such as for cell renewal, immune stimulation and immune tolerance induction, for migration and for the provision of growth factors for beta cell regeneration. This general deficiency state was corroborated by a reduced in vivo proliferation (BrdU incorporation) of the cells and the reduced expression in FACS analysis of CD86, CCR5, CD103, Clec9a, CD24 and CD200R3 on the cells. 2) A hyper reactivity of these cells to LPS correlated with an enhanced pro-inflammatory state characterized by altered expression of a number of classical pro-inflammatory factors and cytokines. Conclusion: The NOD CD11c+CD8- DCs seem to be Janus-faced depending on the conditions: Deficient in steady state with reduced immune stimulation capabilities also for tolerance induction; over-inflammatory with a molecular profile suggesting a preferential stimulatory capacity for Th1 cells when encountering a Pathogen-Associated Molecular Pattern (PAMP) in the form of LPS.
The gene expression profile of CD11c+ CD8α- dendritic cells in the pre-diabetic pancreas of the NOD mouse.
Sex, Age, Specimen part, Treatment
View SamplesBipolar disorder (BD) is a psychiatric disorder in which the core feature is pathological disturbance in mood ranging from extreme elation (mania) to severe depression. Study has shown an aberrant pro-inflammatory status of monocytes/macrophages in mood disorders. Therefore, this study aimed at studying the monocyte compartment in Bipolar Disorder, by transcription profiling of CD14+ monocytes in patients and controls.
A discriminating messenger RNA signature for bipolar disorder formed by an aberrant expression of inflammatory genes in monocytes.
Sex, Age, Specimen part, Disease
View SamplesThe IFN type I signature is present in over half of primary Sjgrens syndrome (pSS) patients and associated with higher disease-activity and autoantibody presence. Plasmacytoid dendritic cells (pDCs) are considered to be the source of enhanced IFN type I expression. The objective of this study was to unravel the molecular pathways underlying IFN type I bioactivity in pDCs of pSS patients.
Contrasting expression pattern of RNA-sensing receptors TLR7, RIG-I and MDA5 in interferon-positive and interferon-negative patients with primary Sjögren's syndrome.
Sex, Specimen part, Disease, Disease stage
View SamplesNKL homeobox genes encode developmental transcription factors regulating basic processes in cell differentiation. According to their physiological expression pattern in early hematopoiesis and B-cell development, particular members of this homeobox gene subclass constitute an NKL-code. These B-cell specific genes generate a regulatory network and their deregulation is implicated in B-cell lymphomagenesis. Epstein-Barr virus (EBV) infects B-cells and influences the activity of signalling pathways including JAK/STAT and several genes encoding developmental regulators. Therefore, EBV-infection impacts the pathogenesis and the outcome of B-cell malignancies including Hodgkin lymphoma and diffuse large B-cell lymphoma (DLBCL). Here, we isolated EBV-positive and EBV-negative subclones from the DLBCL derived cell line DOHH-2. These subclones served as model to investigate the role of EBV in deregulation of the B-cell specific NKL-code members HHEX, HLX, MSX1 and NKX6-3. We showed that the EBV-encoded factors LMP1 and LMP2A activated the expression of HLX via STAT3. HLX in turn repressed NKX6-3, SPIB and IL4R which normally mediate plasma cell differentiation. In addition, HLX repressed pro-apoptotic factor BCL2L11/BIM supporting cell survival. Thus, EBV aberrantly activated HLX thereby disturbing both B-cell differentiation and apoptosis in DLBCL. The results of our study contribute to better understand the pathogenic role of EBV in B-cell malignancies.
The NKL-code for innate lymphoid cells reveals deregulated expression of NKL homeobox genes HHEX and HLX in anaplastic large cell lymphoma (ALCL).
Cell line, Treatment
View SamplesNKL homeobox genes encode developmental transcription factors regulating basic processes in cell differentiation. According to their physiological expression pattern in early hematopoiesis and B-cell development, particular members of this homeobox gene subclass constitute an NKL-code. These B-cell specific genes generate a regulatory network and their deregulation is implicated in B-cell lymphomagenesis. Epstein-Barr virus (EBV) infects B-cells and influences the activity of signalling pathways including JAK/STAT and several genes encoding developmental regulators. Therefore, EBV-infection impacts the pathogenesis and the outcome of B-cell malignancies including Hodgkin lymphoma and diffuse large B-cell lymphoma (DLBCL). Here, we isolated EBV-positive and EBV-negative subclones from the DLBCL derived cell line DOHH-2. These subclones served as model to investigate the role of EBV in deregulation of the B-cell specific NKL-code members HHEX, HLX, MSX1 and NKX6-3. We showed that the EBV-encoded factors LMP1 and LMP2A activated the expression of HLX via STAT3. HLX in turn repressed NKX6-3, SPIB and IL4R which normally mediate plasma cell differentiation. In addition, HLX repressed pro-apoptotic factor BCL2L11/BIM supporting cell survival. Thus, EBV aberrantly activated HLX thereby disturbing both B-cell differentiation and apoptosis in DLBCL. The results of our study contribute to better understand the pathogenic role of EBV in B-cell malignancies.
The NKL-code for innate lymphoid cells reveals deregulated expression of NKL homeobox genes HHEX and HLX in anaplastic large cell lymphoma (ALCL).
Cell line, Treatment
View SamplesHomeobox genes encode transcription factors regulating basic processes in cell differentiation during embryogenesis and in the adult. Recently, we have reported the NKL-code which describes physiological expression patterns of nine NKL homeobox genes in early hematopoiesis and in lymphopoiesis including main stages of T-, B- and NK-cell development. Aberrant activity of NKL homeobox genes is involved in the generation of hematological malignancies including T-cell leukemia. Here, we searched for deregulated NKL homeobox genes in main entities of T-cell lymphomas comprising peripheral T-cell lymphoma (PTCL), angioimmunoblastic T-cell lymphoma (AITL), anaplastic large cell lymphoma (ALCL), adult T-cell leukemia/lymphoma (ATLL), hepatospleenic T-cell lymphoma (HSTL), and NK/T-cell lymphoma (NKTL). Our data revealed in all types altogether 19 aberrantly overexpressed genes, demonstrating that deregulated NKL homeobox genes play a significant role in T-cell lymphomas as well. For detailed analyses we focused on NKL homeobox gene MSX1 which is normally expressed in NK-cells and aberrantly activated in T-cell leukemia. This gene was overexpressed in subsets of HSTL patients and HSTL-derived sister cell lines DERL-2 and DERL-7 which served as models to identify mechanisms of deregulation. We performed genomic and expression profiling and whole genome sequencing and revealed mutated and deregulated gene candidates including the fusion gene CD53-PDGFRB exclusively expressed in DERL-2. Subsequent knockdown experiments allowed the construction of an aberrant network involved in MSX1 deregulation containing chromatin factors AUTS2 and H3B/H3.1, PDGF- and BMP-signalling pathways, and homeobox genes NKX2-2 and PITX1. The gene encoding AUTS2 is located at 7q11 and may represent a basic target of the HSTL hallmark aberration i(7q). Our data indicate both oncogenic and tumor suppressor functions of MSX1 in HSTL, reflecting its activity in early lineage differentiation of T- and NK-cells and the presence of NK-cell like characteristics in malignant HSTL cells. In this context, NKL homeobox gene MSX1 may represent a selective target in HSTL tumor evolution. Together, the data highlight an oncogenic role of deregulated NKL homeobox genes in T-cell lymphoma and identified MSX1 as a novel player in HSTL, involved in aberrant NK- and T-cell differentiation.
Deregulated expression of NKL homeobox genes in T-cell lymphomas.
Disease, Disease stage, Cell line
View SamplesT-cell acute lymphoblastic leukemia (T-ALL) cells represent developmentally arrested T-cell progenitors, subsets of which aberrantly express homeobox genes of the NKL subclass, including TLX1, TLX3, NKX2-1, NKX2-5, NKX3-1 and MSX1. Here, we analyzed the transcriptional landscape of all 48 members of the NKL homeobox gene subclass in CD34+ hematopoietic stem cells (HSCs) and during lymphopoiesis, identifying activities of 9 particular genes. Four of these were expressed in HSCs (HHEX, HLX1, NKX2-3 and NKX3-1) and three in common lymphoid progenitors (HHEX, HLX1 and MSX1). Interestingly, our data indicated downregulation of NKL homeobox gene transcripts in late progenitors and mature T-cells, a phenomenon which might explain the oncogenic impact of this group of genes in T-ALL. Using MSX1-expressing T-ALL cell lines as models, we showed that HHEX activates while HLX1, NKX2-3 and NKX3-1 repress MSX1 transcription, demonstrating the mutual regulation and differential activities of these homeobox genes. Analysis of a public T-ALL expression profiling data set comprising 117 patient samples identified 20 aberrantly activated members of the NKL subclass, extending the number of known NKL homeobox oncogene candidates. While 7/20 genes were also active during hematopoiesis, the remaining 13 showed ectopic expression. Finally, comparative analyses of T-ALL patient and cell line profiling data of NKL-positive and NKL-negative samples indicated absence of common target genes but instead highlighted deregulation of apoptosis as common oncogenic effect. Taken together, we present a comprehensive survey of NKL homeobox genes in early hematopoiesis, T-cell development and T-ALL, showing that these genes generate an NKL-code for the diverse stages of lymphoid development which might be fundamental for regular differentiation.
NKL homeobox gene activities in hematopoietic stem cells, T-cell development and T-cell leukemia.
Cell line
View SamplesWe used microarrays to detail the global program of gene expression underlying stemness of hematopoietic cells.
NKL homeobox gene activities in hematopoietic stem cells, T-cell development and T-cell leukemia.
Specimen part, Disease
View SamplesBased on the assumption that molecular mechanisms involved in cancerogenesis are characterized by groups of coordinately expressed genes, we developed and validated a novel method for analyzing transcriptional data called Correlated Gene Set Analysis (CGSA). Using 50 extracted gene sets we identified three different profiles of tumors in a cohort of 364 Diffuse large B-cell (DLBCL) and related mature aggressive B-cell lymphomas other than Burkitt lymphoma. The first profile had high level of expression of genes related to proliferation whereas the second profile exhibited a stromal and immune response phenotype. These two profiles were characterized by a large scale gene activation affecting genes which were recently shown to be epigenetically regulated, and which were enriched in oxidative phosphorylation, energy metabolism and nucleoside biosynthesis. The third and novel profile showed only low global gene activation similar to that found in normal B cells but not cell lines. Our study indicates novel levels of complexity of DLBCL with low or high large scale gene activation related to metabolism and biosynthesis and, within the group of highly activated DLBCLs, differential behavior leading to either a proliferative or a stromal and immune response phenotype.
Massive transcriptional perturbation in subgroups of diffuse large B-cell lymphomas.
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