The first site exhibiting hematopoietic activity in mammalian development is the yolk sac blood island, which originates from the hemangioblast. Here we performed differentiation assays, as well as genome-wide molecular and functional studies in BL-CFCs to gain insight into the function of the essential Ldb1 factor in early primitive hematopoietic development. We show that the previously reported lack of yolk sac hematopoiesis and vascular development in Ldb1-/- mouse result from a decreased number of hemangioblasts and a block in their ability to differentiate into erythroid and endothelial progenitor cells. Transcriptome analysis and correlation with the genome wide binding pattern of Ldb1 in hemangioblasts revealed a number of direct target genes and pathways misregulated in the absence of Ldb1. The regulation of essential developmental factors by Ldb1 defines it as an upstream transcriptional regulator of hematopoietic/endothelial development. We show the complex interplay that exists between transcription factors and signaling pathways during the very early stages of hematopoietic/endothelial development and the specific signalling occurring in hemangioblasts in contrast to more advanced hematopoietic developmental stages. Finally, by revealing novel genes and pathways, not previously associated with early development, our study provides novel candidate targets to manipulate the differentiation of hematopoietic and/or endothelial cells.
Genome-wide analysis shows that Ldb1 controls essential hematopoietic genes/pathways in mouse early development and reveals novel players in hematopoiesis.
Specimen part
View SamplesThe role of Tfr1 in non-erythroid tissues remains elusive due to the embryonic lethality of the Tfr1 global knockout mouse model. To bypass this problem, we generated a mouse model in which Tfr1 was conditionally deleted in intestinal epithelial cells (IECs). These mice developed severe IEC disruption, characterized by blunted villi, edema, loss of proliferative intervillus IECs, accumulation of lipids, and early neonatal lethality. Strikingly, a wide range of genes associated with epithelial-to-mesenchymal transition were highly upregulated in IEC lacking Tfr1. Additionally, candidate vesicular transport and sorting genes implicated in lipid absorption and trafficking were downregulated. Surprisingly, the presence of a mutant allele of Tfr1, which is unable to bind to iron-loaded transferrin, was capable of rescuing the lethality, intestinal epithelial homeostasis, and proliferation in a majority of the Tfr1 conditional knockout mice.
Noncanonical role of transferrin receptor 1 is essential for intestinal homeostasis.
Specimen part
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Integrative genomic signatures of hepatocellular carcinoma derived from nonalcoholic Fatty liver disease.
Age, Specimen part, Disease
View SamplesLiver global gene expression patterns of 9 GNMT-knockout mice histopathologically determined to have non-alcoholic steatohepatitis (NASH) and hepatocellular carcinoma (HCC) together with 10 MAT1A-knockout mice histopathologically determined to have steatosis and NASH. All these have their respective wild type patterns. These were analyzed to define signatures to study the pathogenesis of NAFLD-derived HCC, explore which subtypes of cancers can be investigated using mouse models and define a signature of HCC differential survival that can be used to characterize HCC subtypes of different survival derived from mixed etiologies.
Integrative genomic signatures of hepatocellular carcinoma derived from nonalcoholic Fatty liver disease.
Age, Specimen part, Disease
View SamplesZebrafish have the remarkable ability to regenerate body parts including the heart, spinal cord and fins by a process referred to as epimorphic regeneration. Recent studies have illustrated that similar to adult zebrafish, early life stage-larvae also possess the ability to regenerate the caudal fin. A comparative genomic analysis was used to determine the degree of conservation in gene expression among the regenerating adult caudal fin, adult heart and larval fin. Results indicate that these tissues respond to amputation/injury with strikingly similar genomic responses. Comparative analysis revealed raldh2, a rate-limiting enzyme for the synthesis of Retinoic acid (RA), as one of the highly induced genes across the three regeneration platforms.
Comparative expression profiling reveals an essential role for raldh2 in epimorphic regeneration.
No sample metadata fields
View SamplesFollowing the identification of a critical time window of Blood Brain Barrier formation in the mouse embryo, we aimed to identify genes important for barriergenesis. To this end, we isolated cortical and lung E13.5 endothelial cells and compared expression between the two populations.
Mfsd2a is critical for the formation and function of the blood-brain barrier.
Specimen part
View SamplesSkeletal muscle atrophy is a consequence of many diseases, environmental insults, inactivity, age and injury. Atrophy is characterized by active degradation and removal of contractile proteins and a reduction in fiber size. Animal models have been extensively used to identify pathways leading to atrophic conditions. Here we have used genome-wide expression profiling analysis and quantitative PCR to identify the molecular changes that occur in two clinically relevant animal mouse models of muscle atrophy, hindlimb casting and Achilles tendon laceration (tenotomy). Gastrocnemius muscle samples were collected 2, 7 and 14 days after insult. The total amount of muscle loss as measured by wet weight and muscle fiber size was equivalent between models, although tenotomy resulted in a more rapid induction of muscle atrophy. Furthermore, tentomy resulted in the regulation of significantly more mRNA transcripts then casting. Analysis of the regulated genes and pathways suggest that the mechanism of atrophy is distinct between these models. The degradation following casting appears ubiquitin-proteasome-mediated while degradation following tenotomy appears lysosomal and matrix-metalloproteinase (MMP)-mediated. This data suggests that there are multiple mechanisms leading to muscle atrophy and that specific therapeutic agents may be necessary to combat the atrophy seen under different conditions.
Distinct protein degradation profiles are induced by different disuse models of skeletal muscle atrophy.
Sex, Specimen part, Treatment, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Anchorage-independent cell growth signature identifies tumors with metastatic potential.
Specimen part, Cell line
View SamplesCultured cancer cells exhibit substantial phenotypic heterogeneity when measured in a variety of ways such as sensitivity to drugs or the capacity to grow under various conditions. Among these, the ability to exhibit anchorage-independent cell growth (colony forming capacity in semisolid media) has been considered to be fundamental in cancer biology because it has been connected with tumor cell aggressiveness in vivo such as tumorigenic and metastatic potentials, and also utilized as a marker for in vitro transformation. Although multiple genetic factors for anchorage-independence have been identified, the molecular basis for this capacity is still largely unknown. To investigate the molecular mechanisms underlying anchorage-independent cell growth, we have used genome-wide DNA microarray studies to develop an expression signature associated with this phenotype. Using this signature, we identify a program of activated mitochondrial biogenesis associated with the phenotype of anchorage-independent growth and importantly, we demonstrate that this phenotype predicts potential for metastasis in primary breast and lung tumors.
Anchorage-independent cell growth signature identifies tumors with metastatic potential.
No sample metadata fields
View SamplesWe investigated the ability of transferrin receptor1 (TfRc) knockout cells to populate different domains of the developing kidney by using a chimeric approach. The TfRc cells developed into all segments of the developing nephron, but there was a relative exclusion from the ureteric bud and a positive bias towards the stromal compartment. Here we conducted a microarray analysis of differential gene expression between TfRc deficient and wild type (wt) cells in chimeric embryonic kidneys derived from embryos created by blastocyst injection of wt blastocysts with TfRc-/- green fluorescent protein-expressing (GFP+) embryonic stem cells.
Scara5 is a ferritin receptor mediating non-transferrin iron delivery.
No sample metadata fields
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