The transcription factor Evi1 is essential for the formation and maintenance of hematopoietic stem cells, and induces clonal dominance with malignant progression upon constitutive activation by chromosomal rearrangements or transgene integration events. To understand the immediate and adaptive response of primary murine hematopoietic cells to the transcriptional upregulation of Evi1, we developed an inducible lentiviral vector system with a robust expression switch. We found that Evi1 delays differentiation and promotes survival in myeloid culture conditions, orchestrating a battery of genes involved in stemness (Aldh1a1, Ly6a [Sca1], Abca1, Epcam, among others). Importantly, Evi1 suppresses Cyclins and Cyclin-dependent kinases (Cdk), while it upregulates Cdk inhibitors, inducing quiescence in various proliferation-inducing cytokine conditions and operating in a strictly dose-dependent manner. Hematopoietic cells with persisting Evi1-induction tend to adopt a relatively low expression level. We thus classify Evi1 as a dormancy-inducing oncogene, likely requiring epigenetic and genetic compensation for cell expansion and malignant progression.
Activation of Evi1 inhibits cell cycle progression and differentiation of hematopoietic progenitor cells.
Specimen part
View SamplesPreimplantation Genetic Testing (PGT), which encompasses both Preimplantation Genetic Diagnosis (PGD) and Preimplantation Genetic Screening (PGS), is a form of prenatal screening done on embryos conceived through assisted reproduction techniques (ART) prior to the initiation of pregnancy to ensure that only select embryos are used for transfer. PGT is typically performed on 8-cell embryos derived from either in vitro fertilization or intracytoplasmic sperm injection (ICSI) followed by extended culture. PGT requires a highly invasive embryo biopsy procedure that involves 1) incubating embryos in divalent-cation-deficient medium to disrupt cell adhesion, 2) breaching the protective zona pellucida with acid Tyrodes, laser drilling, or mechanical force and 3) aspirating one or two blastomeres. In this study we developed a mouse model of the embryo biopsy procedure inherent to PGT to determine the effect of various aspects of the procedure (incubation in Ca2+/Mg2+-free medium (CMF), acid Tyrodes treatment, blastomere aspiration), performed individually or in combination, on global patterns of gene expression in the resulting blastocysts.
The effect of blastomere biopsy on preimplantation mouse embryo development and global gene expression.
Sex
View SamplesSmall RNAs, such as miRNAs and siRNAs, are involved in gene regulation in a variety of systems, including mouse oocytes. Dicer is a ribonuclease III enzyme essential for miRNA and siRNA biosynthesis. In an effort to uncover the function of small RNAs during oocyte growth, we specifically deleted Dicer in growing oocytes and analyzed the global pattern of gene expression in these Dicer-deficient oocytes.
MicroRNA activity is suppressed in mouse oocytes.
Sex, Specimen part
View SamplesBalanced immune responses in airways of patients with asthma are crucial to succesful clearance of viral infection and proper asthma control.
Rhinovirus-induced epithelial RIG-I inflammasome suppresses antiviral immunity and promotes inflammation in asthma and COVID-19.
Subject, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Polycomb repressive complex 2 is required for MLL-AF9 leukemia.
Specimen part, Disease, Disease stage
View SamplesWe evaluated gene expression changes in murine leukemia caused by retroviral overexpression of MLL-AF9. We compared wild-type (WT) leukemia cells with mutant leukemia cells after cre-mediated inactivation of homozygous conditional alleles for Ezh2 or Eed, both of which are components of the Polycomb Repressive Complex2.
Polycomb repressive complex 2 is required for MLL-AF9 leukemia.
Specimen part, Disease, Disease stage
View SamplesWe evaluated gene expression changes in secondary recipient murine leukemia caused by retroviral overexpression of MLL-AF9. We compared wild-type (WT) leukemia cells with mutant leukemia cells after cre-mediated inactivation of a homozygous conditional allele for Ezh2, a component of the Polycomb Repressive Complex2.
Polycomb repressive complex 2 is required for MLL-AF9 leukemia.
Specimen part, Disease, Disease stage
View Samplesprenatal stress response, genetic modification
Differential effects of prenatal stress in 5-Htt deficient mice: towards molecular mechanisms of gene × environment interactions.
Sex, Specimen part, Treatment
View SamplesUniparental parthenotes are considered an unwanted byproduct of in vitro fertilization. In utero parthenote development is severely compromised by defective organogenesis and in particular by defective cardiogenesis. Although developmentally compromised, apparently pluripotent stem cells can be derived from parthenogenetic blastocysts. Here we hypothesized that nonembryonic parthenogenetic stem cells (PSCs) can be directed toward the cardiac lineage and applied to tissue-engineered heart repair. We first confirmed similar fundamental properties in murine PSCs and embryonic stem cells (ESCs), despite notable differences in genetic (allelic variability) and epigenetic (differential imprinting) characteristics. Haploidentity of major histocompatibility complexes (MHCs) in PSCs is particularly attractive for allogeneic cell-based therapies. Accordingly, we confirmed acceptance of PSCs in MHC-matched allotransplantation. Cardiomyocyte derivation from PSCs and ESCs was equally effective. The use of cardiomyocyte-restricted GFP enabled cell sorting and documentation of advanced structural and functional maturation in vitro and in vivo. This included seamless electrical integration of PSC-derived cardiomyocytes into recipient myocardium. Finally, we enriched cardiomyocytes to facilitate engineering of force-generating myocardium and demonstrated the utility of this technique in enhancing regional myocardial function after myocardial infarction. Collectively, our data demonstrate pluripotency, with unrestricted cardiogenicity in PSCs, and introduce this unique cell type as an attractive source for tissue-engineered heart repair.
Parthenogenetic stem cells for tissue-engineered heart repair.
Specimen part
View SamplesKnockdown of the transcription factor PU.1 (Spi1) leads to acute myeloid leukemia (AML) in mice. We examined the transcriptome of PU.1 knockdown hematopoietic stem cells (HSC) in the preleukemic phase by linear amplification and genome-wide array analysis to identify transcriptional changes preceding malignant transformation. Hierarchical cluster analysis and principal component analysis clearly distinguished PU.1 knockdown from wildtype HSC. Jun family transcription factors c-Jun and JunB were among the top downregulated targets. Retroviral restoration of c-Jun expression in bone marrow cells of preleukemic mice partially rescued the PU.1-initiated myelomonocytic differentiation block. Lentiviral restoration of JunB at the leukemic stage led to reduced clonogenic growth, loss of leukemic self-renewal capacity, and prevented leukemia in transplanted NOD-SCID mice. Examination of 305 AML patients confirmed the correlation between PU.1 and JunB downregulation and suggests its relevance in human disease. These results delineate a transcriptional pattern that precedes the leukemic transformation in PU.1 knockdown HSC and demonstrate that decreased levels of c-Jun and JunB contribute to the development of PU.1-induced AML by blocking differentiation (c-Jun) and increasing self-renewal (JunB). Therefore, examination of disturbed gene expression in HSC can identify genes whose dysregulation is essential for leukemic stem cell function and are targets for therapeutic interventions.
Essential role of Jun family transcription factors in PU.1 knockdown-induced leukemic stem cells.
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