Ebf1 is a transcription factor with documented, and dose dependent, functions in both normal and malignant B-lymphocyte development. In order to understand more about the role of Ebf1 in malignant transformation, we have investigated the impact of reduced functional Ebf1 dose on early B-cell progenitors. Gene expression analysis in loss and gain of function analysis suggested that Ebf1 was involved in the regulation of genes of importance for DNA repair as well as cell survival. Investigation of the level of DNA damage in steady state as well as after induction of DNA damage by UV light supported that pro-B cells lacking one functional allele of Ebf1 display a reduced ability to repair DNA damage. This was correlated to a reduction in expression of Rad51 and combined analysis of published 4C and chromatin Immuno precipitation data suggested that this gene is a direct target for Ebf1. Even though the lack of one allele of Ebf1 did not result in any dramatic increase of tumor formation, we noted a dramatic increase in the formation of pro-B cell leukemia in mice carrying a combined heterozygote mutation in the Ebf1 and Pax5 genes. Even though the tumors were phenotypically similar and stable, we noted a large degree of molecular heterogeneity well in line with a mechanism involving impaired DNA repair. Our data support the idea that Ebf1 controls homologous DNA repair in a dose dependent manner and that this may explain the frequent involvement of Ebf1 in human leukemia
Ebf1 heterozygosity results in increased DNA damage in pro-B cells and their synergistic transformation by Pax5 haploinsufficiency.
Specimen part, Cell line, Time
View SamplesThe blood-brain barrier (BBB) consists of specific physical barriers, enzymes and transporters, which together maintain the necessary extracellular environment of the central nervous system (CNS). The main physical barrier is found in the CNS endothelial cell, and depends on continuous complexes of tight junctions combined with reduced vesicular transport. Other possible constituents of the BBB include extracellular matrix, astrocytes and pericytes, but the relative contribution of these different components to the BBB remains largely unknown. Here we demonstrate a direct role of pericytes at the BBB in vivo. Using a set of adult viable pericyte-deficient mouse mutants we show that pericyte deficiency increases the permeability of the BBB to water and a range of low-molecular-mass and high-molecular-mass tracers. The increased permeability occurs by endothelial transcytosis, a process that is rapidly arrested by the drug imatinib. Furthermore, we show that pericytes function at the BBB in at least two ways: by regulating BBB-specific gene expression patterns in endothelial cells, and by inducing polarization of astrocyte end-feet surrounding CNS blood vessels. Our results indicate a novel and critical role for pericytes in the integration of endothelial and astrocyte functions at the neurovascular unit, and in the regulation of the BBB.
Pericytes regulate the blood-brain barrier.
Sex, Age, Specimen part
View SamplesProgressive tissue fibrosis is a major cause of morbidity, and idiopathic pulmonary fibrosis (IPF) is a terminal illness characterized by unremitting matrix deposition in the lung with very limited choice of therapies. The imcomplete understanding of the mechanisms of progressive fibrosis curbs the progress in therapeutics development. Of which, the origin of fibrotic fibroblasts has been poorly defined during the pathogenesis of tissue fibrosis. Here, we fate-mapped a early embryonic transcription factor T-box gene 4 (Tbx4)-derived mesenchymal progenitors in injured adult lung and found that Tbx4+ lineage cells are the major source of myofibroblasts. The ablation of Tbx4+ cells or disruption of Tbx4 signaling attenuated lung fibrosis in bleomycin injury model in mice in vivo. Furthermore, Tbx4+ fibroblasts are more invasive and the regulation of fibroblast invasiveness by Tbx4 is through mediating hyaluronan synthase 2 (HAS2). This study identified a major mesenchymal transcription factor driving the development of fibrotic fibroblasts during lung fibrosis. Understanding the origin, signaling, and functions of these fibroblasts would prove pivotal in the development of therapeutics for patients with progressive fibrotic diseases.
Transcription factor TBX4 regulates myofibroblast accumulation and lung fibrosis.
Specimen part
View SamplesExpression profiling of cultured HL-1 cardiomyocytes subjected to hypoxia for 8 hours.
The VLDL receptor promotes lipotoxicity and increases mortality in mice following an acute myocardial infarction.
Cell line
View SamplesOocyte maturation is accompanied by a transition from mRNA stability to instability. We investigated the role of DCP1A and DCP2, proteins responsible for mRNA decapping, in mRNA destabilization during mouse oocyte maturation.
Maternally recruited DCP1A and DCP2 contribute to messenger RNA degradation during oocyte maturation and genome activation in mouse.
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View SamplesREST is a master regulator of genes that are involved in the acqusition of neuronal fate. The role of REST is not well understood so we attempted to investigate the role of REST in the development of neural cells by analysing the genes that are upregulated when REST is knocked down via shRNA
REST regulates the pool size of the different neural lineages by restricting the generation of neurons and oligodendrocytes from neural stem/progenitor cells.
Specimen part
View SamplesIdentification of all genes expressed by mouse olfactory sensory neurons; genes expressed in mature neurons, immature neurons, or both were distinguished. Independent validation of enrichment ratio values supported by statistical assessment of error rates was used to build a database of statistical probabilities of the expression of all mRNAs detected in mature neurons, immature neurons, both types of neurons (shared), and the residual population of all other cell types.
Genomics of mature and immature olfactory sensory neurons.
Sex, Specimen part
View SamplesAtherosclerosis and pressure overload are major risk factors for the development of heart failure in patients. Cardiac hypertrophy often precedes the development of heart failure. However, underlying mechanisms are incompletely understood. To investigate pathomechanisms underlying the transition from cardiac hypertrophy to heart failure we used experimental models of atherosclerosis- and pressure overload-induced cardiac hypertrophy and failure, i.e. apolipoprotein E (apoE)-deficient mice, which develop heart failure at an age of 18 months, and non-transgenic C57BL/6J (B6) mice with heart failure triggered by 6 months of pressure overload induced by abdominal aortic constriction (AAC). The development of heart failure was monitored by echocardiography, invasive hemodynamics and histology. The microarray gene expression study of cardiac genes was performed with heart tissue from failing hearts relative to hypertrophic and healthy heart tissue, respectively. The microarray study revealed that the onset of heart failure was accompanied by a strong up-regulation of cardiac lipid metabolism genes involved in fat synthesis, storage and oxidation.
Up-regulation of the cardiac lipid metabolism at the onset of heart failure.
Age, Specimen part, Disease
View SamplesHow secondary CD4 T cell effectors, derived from resting memory cells, differ from primary cells, derived from nave precursors, and how such differences impact recall responses to pathogens is unknown.
Memory CD4+ T-cell-mediated protection depends on secondary effectors that are distinct from and superior to primary effectors.
Specimen part
View SamplesHeart failure is a leading cause of cardiovascular mortality with limited options for treatment. We used 18 month-old apolipoprotein E (apoE)- deficient mice as a model of atherosclerosis-induced heart failure to analyze whether the anti-ischemic drug ranolazine could retard the progression of heart failure. The study showed that 2 months of ranolazine treatment improved cardiac function of 18 month-old apoE-deficient mice with symptoms of heart failure as assessed by echocardiography. To identify changes in cardiac gene expression induced by treatment with ranolazine a microarray study was performed with heart tissue from failing hearts relative to ranolazine-treated and healthy control hearts. The microarray approach identified heart failure-specific genes that were normalized during treatment with the anti-ischemic drug ranolazine.
Up-regulation of the cardiac lipid metabolism at the onset of heart failure.
Age, Specimen part, Disease, Treatment
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