The Core Binding Factor (CBF) protein RUNX1 is a master regulator of definitive hematopoiesis, crucial for hematopoietic stem cell (HSC) emergence during ontogeny, which also plays vital roles in adult mice, in regulating the correct specification of numerous blood lineages. Akin to the other mammalian Runx genes, Runx1 has two promoters P1 (distal) and P2 (proximal) which generate distinct protein isoforms. The activities and specific relevance of these two promoters in adult hematopoiesis remain to be fully elucidated. Utilizing a dual reporter model, we demonstrate here that the distal P1 promoter is broadly active in adult hematopoietic stem and progenitor cell (HSPC) populations. By contrast, the activity of the proximal P2 promoter is more restricted and its upregulation, in both the immature Lineage- Sca1high cKithigh (LSK) and bipotential Pre-Megakaryocytic/Erythroid Progenitor (PreMegE) populations, coincides with a loss of erythroid specification. Accordingly, the PreMegE population can be prospectively separated into "pro-erythroid" and "pro-megakaryocyte" populations based on Runx1 P2 activity. Comparative gene expression analyses between Runx1 P2+ and P2- populations indicated that the level of CD34 expression could substitute for P2 activity to distinguish these two cell populations in wild type (WT) bone marrow (BM). Prospective isolation of these two populations will provide the opportunity to further investigate and define the molecular mechanisms involved in megakaryocytic/erythroid (Mk/Ery) cell fate decisions. Moreover, comparison of a RUNX1C null (KO) PreMegE to its WT counterpart demonstrated considerably enhanced erythroid specification at the expense of megakaryopoiesis in the absence of P1-specified RUNX1C expression. Overall design: mRNA profiles of wild type (WT), Runx1 P2-hCD4+ (P2+), Runx1 P2-hCD4- (P2-) and RUNX1C knockout (KO) bone marrow Pre-Megakaryocyte/Erythroid (PreMegE) progenitors were generated from young adult (12-16 weeks) mice by deep sequencing, in triplicate, using Illumina NextSeq 500.
RUNX1B Expression Is Highly Heterogeneous and Distinguishes Megakaryocytic and Erythroid Lineage Fate in Adult Mouse Hematopoiesis.
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View SamplesIn recent years, highly detailed characterization of adult bone marrow (BM) myeloid progenitors has been achieved and, as a result, the impact of somatic defects on different hematopoietic lineage fate decisions can be precisely determined. Fetal liver (FL) hematopoietic progenitor cells (HPCs) are poorly characterized in comparison, potentially hindering the study of the impact of genetic alterations on midgestation hematopoiesis. Numerous disorders, for example infant acute leukaemias, have in utero origins and their study would therefore benefit from the ability to isolate highly purified progenitor subsets. We previously demonstrated that a Runx1 distal promoter (P1)-GFP::proximal promoter (P2)-hCD4 dual-reporter mouse (Mus musculus) model can be used to identify adult BM progenitor subsets with distinct lineage preferences. In this study, we undertook the characterization of the expression of Runx1-P1-GFP and P2-hCD4 in FL. Expression of P2-hCD4 in the FL immunophenotypic Megakaryocyte-Erythroid Progenitor (MEP) and Common Myeloid Progenitor (CMP) compartments corresponded to increased granulocytic/monocytic/megakaryocytic and decreased erythroid specification. Moreover, Runx1-P2-hCD4 expression correlated with several endogenous cell surface markers' expression, including CD31 and CD45, providing a new strategy for prospective identification of highly purified fetal myeloid progenitors in transgenic mouse models. We utilized this methodology to compare the impact of the deletion of either total RUNX1 or RUNX1C alone and to determine the fetal HPCs lineages most substantially affected. This new prospective identification of FL progenitors therefore raises the prospect of identifying the underlying gene networks responsible with greater precision than previously possible. Overall design: mRNA profiles of single sorted Runx1 P2-hCD4+ Megakaryocyte Erythroid Progenitors (MEPs), Runx1 P2-hCD4- MEPs, Runx1 P2-hCD4+ Common Myeloid Progenitors (CMPs) and Runx1 P2-hCD4- CMPs from Mouse E14.5 Runx1 P2-GFP::P2-hCD4/+ Fetal Liver Samples
A novel prospective isolation of murine fetal liver progenitors to study in utero hematopoietic defects.
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View SamplesCD44+/CD24- subpopulation of normal and cancerous breast epithelial cells are suggested to have stem cell properties. The goal of this study was to identify gene expression differences between CD44+/CD24- and CD44-/CD24+ subpopulation of cells from a same cell lines. We selected MCF-10A cells, which are immortalized derived from a fibrocystic breast disease. These cells are immortalized but not transformed and express basal cell markers.
SLUG/SNAI2 and tumor necrosis factor generate breast cells with CD44+/CD24- phenotype.
Specimen part
View SamplesHuman adult mesenchymal stromal cells (hMSC) have the potential to differentiate into chondrogenic, adipogenic or osteogenic lineages, providing a potential source for tissue regeneration. An important issue for efficient bone regeneration is to identify factors that can be targeted to promote the osteogenic potential of hMSCs. Using transcriptomic analysis, we found that integrin alpha5 (ITGA5) expression is upregulated during dexamethasone-induced hMSCs osteoblast differentiation. Gain-of-function studies showed that ITGA5 promotes the expression of osteoblast phenotypic markers as well as in vitro osteogenesis in hMSCs. Downregulation of endogenous ITGA5 using shRNA blunted osteoblast marker expression and osteogenic differentiation. Pharmacological and molecular analyses showed that the enhanced hMSCs osteoblast differentiation induced by ITGA5 was mediated by activation of FAK/ERK1/2-MAPKs and PI3K signaling pathways. Remarkably, activation of ITGA5 using a specific antibody that primes the integrin or a peptide that specifically activates ITGA5 was sufficient to enhance ERK1/2-MAPKs and PI3K signaling and to promote osteoblast differentiation and osteogenic capacity of hMSCs. We also demonstrate that hMSCs engineered to over-express ITGA5 exhibited a marked increase in their osteogenic potential in vivo. These findings not only reveal that ITGA5 is required for osteoblast differentiation of adult human MSCs but also provide a novel targeted strategy using ITGA5 agonists to promote the osteogenic capacity of hMSCs, which may be used for tissue regeneration in bone disorders where the recruitment or capacity of MSCs is compromised.
Priming integrin alpha5 promotes human mesenchymal stromal cell osteoblast differentiation and osteogenesis.
Sex, Age, Specimen part, Treatment
View SamplesThe aim of our study was to identify gene expression profiles of ductal and lobular carcinomas in relation to normal ductal and lobular cells. We examined ten mastectomy specimens from postmenopausal breast cancer patients. Ductal and lobular tumor and normal cells were microdissected from cryosections. Fifty nanograms of total RNA were amplified and labeled by PCR and in vitro transcription. GCOS pairwise comparison algorithm and rank products have identified multiple genes that are differentially expressed in comparisons between ductal and lobular tumor and normal cell types. The results suggest that these genes are involved in epithelial-mesenchymal transition, TGFbeta and Wnt signaling. These changes are present in both tumor types but appear to be more prominent in lobular carcinomas.
Novel markers for differentiation of lobular and ductal invasive breast carcinomas by laser microdissection and microarray analysis.
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