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
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Reprogramming factor expression initiates widespread targeted chromatin remodeling.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Developmental stage-specific interplay of GATA1 and IGF signaling in fetal megakaryopoiesis and leukemogenesis.
Specimen part, Disease, Cell line, Treatment
View SamplesIn this project, we studied a mouse model of human Down Syndrome (DS) megakaryocytic leukemia involving mutations in the GATA1 transcription factor (called GATA1s mutation). The model was generated through retroviral insertional mutagenesis in Gata1s mutant fetal liver progenitors. In this study, we analyzed the dependency of these leukemic cells on the Gata1s mutant protein.
Developmental stage-specific interplay of GATA1 and IGF signaling in fetal megakaryopoiesis and leukemogenesis.
Specimen part, Cell line, Treatment
View SamplesIntestinal epithelial cells express the lipopolysaccharide (LPS) receptor Toll-like receptor (TLR4) and are responsive to LPS stimulation. Following LPS exposure, epithelial cells, similar to myeloid cells such as macrophages, acquire a state of tolerance. Innate immune tolerance is characterized by a lack of expression of proinflammatory genes in response to repeated stimulation. Tolerant epithelial cells, however, exhibit sustained expression of a distinct set of genes encoding for proteins involved in metabolism and homeostasis. This study comparatively analyzes the gene expression profile 6 hours after LPS stimulation (acute response) versus 6 hours LPS followed by 90 hours incubation in the absence of LPS (tolerant response).
miR-146a mediates protective innate immune tolerance in the neonate intestine.
Specimen part, Cell line, Treatment
View SamplesThe goal of this study is to develop a Plag1 signature and determine how its overexpression contributes to leukemogenesis.
Developmental stage-specific interplay of GATA1 and IGF signaling in fetal megakaryopoiesis and leukemogenesis.
Cell line
View SamplesThe goal of this study is to derive a mouse model of human Down Syndrome (DS) megakaryocytic leukemia involving mutations in the hematopoietic transcription factor, GATA1 (called GATA1s mutation). We achieved this through transduction of Gata1s mutant fetal progenitors by MSCV-based retrovirus expressing a GFP marker, followed by in vitro selection (for immortalized cell lines), and then in vivo selection (for transformed cell lines) through transplantation.
Developmental stage-specific interplay of GATA1 and IGF signaling in fetal megakaryopoiesis and leukemogenesis.
Specimen part
View SamplesThe goal of this study is to derive a mouse model of human Down Syndrome (DS) megakaryocytic leukemia involving mutations in the hematopoietic transcription factor, GATA1 (called GATA1s mutation). We achieved this through transduction of Gata1s mutant fetal progenitors by MSCV-based retrovirus expressing a GFP marker, followed by in vitro selection (for immortalized cell lines), and then in vivo selection (for transformed cell lines) through transplantation.
Developmental stage-specific interplay of GATA1 and IGF signaling in fetal megakaryopoiesis and leukemogenesis.
Specimen part
View SamplesErg is an ETS family transcription factor frequently overexpressed in human leukemias and has been implicated as a key regulator of hematopoietic stem cells (HSCs). However how Erg controls normal hematopoiesis, particularly at the stem cell level, remains poorly understood. Using homologous recombination, we generated an Erg knockdown allele (Ergkd) in which Erg expression can be restored upon Cre-mediated excision of a Stopper cassette. In Ergkd/+ mice, ~40% reduction in Erg dosage perturbed both fetal liver and bone marrow hematopoiesis by reducing the numbers of Lin-Sca-1+c-Kit+ (LSK) hematopoietic stem and progenitor cells (HSPCs) and megakaryocytic progenitors.
Reduced Erg Dosage Impairs Survival of Hematopoietic Stem and Progenitor Cells.
Specimen part
View SamplesHearts Lacking Caveolin-1 Develop Hypertrophy with Normal Cardiac Substrate Metabolism
Hearts lacking caveolin-1 develop hypertrophy with normal cardiac substrate metabolism.
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