Search results for "Stem cell factor"
showing 10 items of 36 documents
Regulation of hematopoiesis through adhesion receptors
2001
Normal steady-state hematopoiesis takes place in the bone marrow microenvironment. Soluble factors as well as contact interactions between the hematopoietic cells and the marrow microenvironment dictate the fate of hematopoietic stem cells and progenitors. Over the last decade it has become clear that cell-cell and cell-extracellular matrix interactions through adhesion receptors play a major role in the hematopoietic process. They are required for the residence of stem cells and progenitors in the marrow, as well as for homing of stem and progenitor cells to the marrow in the setting of stem cell transplantation. Furthermore, adhesion receptors play an important role in regulation of cell …
IL-4-mediated drug resistance in colon cancer stem cells
2008
Cancer stem cells are defined as cells able to both extensively self-renew and differentiate into progenitors. Cancer stem cells are thus likely to be responsible for maintaining or spreading a cancer, and may be the most relevant targets for cancer therapy. The CD133 glycoprotein was recently described as a reliable cancer stem-like cell marker in colon carcinoma. CD133+ cells are both necessary and sufficient to initiate tumour growth in animal models. The CD133+ cell population and spheroid cultures contain cells expressing the stem cell marker Musashi-1 which is involved in maintenance of stem cell fate in several tissues and importantly, this expression is maintained in stem-like cells…
XPO1 (Exportin-1) Is a Major Regulator of Human Erythroid Differentiation. Potential Clinical Applications to Decrease Ineffective Erythropoiesis of …
2015
Abstract Background We and others have shown that normal human erythroid cell maturation requires a transient activation of caspase-3 at late stages of maturation (Zermati et al, J Exp Med 2001). We further documented that, in human erythroblasts, the chaperone HSP70 is constitutively expressed and, at late stages of maturation, translocates into the nucleus and protects GATA-1, the master transcriptional factor critical for erythropoiesis, from caspase-3 cleavage (Ribeil et al, Nature 2007). During the maturation of human β-TM erythroblasts, HSP70 is sequestrated by excess of α-globin chains in the cytoplasm and as a consequence, GATA-1 is no longer protected from caspase-3 cleavage result…
TLRs control hematopoiesis during infection
2013
Recent research has shown that (i) Toll-like receptor (TLR) agonists drive hematopoietic stem and progenitor cells (HSPCs) to proliferate and differentiate along the myeloid lineage in vitro, and (ii) direct TLR-mediated stimulation of HSPCs also promotes macrophage differentiation in vivo following infection. These new insights demonstrate that TLR signaling in HSPCs, in addition to other TLR-dependent mechanisms, can contribute to HSPC expansion and myeloid differentiation after infection. Evidence is, therefore, mounting that direct TLR-induced programming of hematopoiesis plays a key role in host defense by rapidly replenishing the innate immune system with the cells needed to deal with…
Local administration of antisense phosphorothioate oligonucleotides to the c-kit ligand, stem cell factor, suppresses airway inflammation and IL-4 pr…
2001
Abstract Background: The c-kit ligand, stem cell factor (SCF), is an important activating and chemotactic factor for both mast cells and eosinophils. These cells are known to play a fundamental role in the pathogenesis of asthma. Objective: Our goal was to analyze the functional role of SCF in the pathogenesis of asthma. Methods: The expression of SCF was targeted in fibroblasts, epithelial cells, and locally in a murine model of asthma in mice induced by ovalbumin sensitization with an antisense DNA strategy. Results: We could suppress SCF expression in NIH 3T3 fibroblasts and SP1 epithelial cells by a specific antisense phosphorothioate oligonucleotide overlapping the translation start si…
Expression of KIT (CD117) in Biphasic Pulmonary Blastoma. Novel Data on Histogenesis
2003
Biphasic pulmonary blastoma (BPB) is a rare primary neoplasm of the lung and its histogenesis is still uncertain. It has been proposed that BPB is derived from mesoderm or endoderm. Others suggested an origin from a single pluripotential cell. We present a case of a BPB with emphasis on expression of the stem cell factor receptor KIT (CD117). We describe a 61-year-old male patient with a BPB of the upper right lobe. Immunohistochemical analysis was performed using a panel of several antibodies including anti-CD117. Strong cytoplasmic expression of CD117 was found in the epithelium (cytokeratin-positive) as well as in the spindle cells (cytokeratin-negative). Expression of CD117 in both mese…
Bone marrow failure by cytomegalovirus is associated with an in vivo deficiency in the expression of essential stromal hemopoietin genes.
1997
Bone marrow (BM) failure associated with cytomegalovirus (CMV) infection is a feared complication after clinical BM transplantation. Experiments in long-term BM cultures have indicated that BM stromal cells (BMSC) are targets of productive CMV infection, but an in situ infection of BM stroma remained to be documented, and the pathomechanism is open to question. Here we describe a murine in vivo model of lethal CMV aplastic anemia (CMV-AA). The reconstitution of hematopoietic progenitor cells expressing stem cell factor (SCF) receptor was found to be defective in CMV-AA. While murine CMV replication in permissive parenchymal tissues is cytolytic, the hematopoietic cord was found to be a site…
Stem cell-secreted factor therapy regenerates the ovarian niche and rescues follicles.
2021
Background Ovarian senescence is a normal age-associated phenomenon, but increasingly younger women are affected by diminished ovarian reserves or premature ovarian insufficiency. There is an urgent need for developing therapies to improve ovarian function in these patients. In this context, previous studies suggest that stem cell–secreted factors could have regenerative properties in the ovaries. Objective This study aimed to test the ability of various human plasma sources, enriched in stem cell–secreted factors, and the mechanisms behind their regenerative properties, to repair ovarian damage and to promote follicular development. Study Design In the first phase, the effects of human pla…
Kit Is Expressed by Epithelial Cells In Vivo
2003
In mammalian skin, stem cell factor (SCF) regulates the proliferation and maturation of mast cells and melanocytes, which are thought to be the only cutaneous cells that express the Kit-tyrosine kinase receptor (Kit) and respond to epithelial and mesenchymal-derived SCF. We previously had noted, however, the presence of Kit+ cells in murine hair follicles, in an introepithelial tissue compartment devoid of melanocytes and mast cells. Here we have identified the nature of this Kit+ population of cells in hair follicles of C57BL/6 mice. Anagen hair follicles showed strong Kit immunoreactivity not only in the pigmentary unit above the follicular dermal papilla but also in a much more proximall…
Primary proliferating immature myeloid cells from CML patients are not resistant to induction of apoptosis by DNA damage and growth factor withdrawal.
1996
Induction of apoptosis by growth factor deprivation or gamma-irradiation-induced DNA damage was directly studied in proliferating primary haemopoietic cells derived from CD34-positive cells of 13 CML patients and 12 normal controls. CD34-positive cells were cultured in the presence of appropriate concentrations of SCF and G-CSF for 5–7 d. After gamma irradiation with 500 rad or growth factor deprivation, the fraction of apoptotic cells was assessed by two independent methods applying either measurement of cells incorporating FITC-labelled dUTP by terminal transferase or assessment of the fraction of cells with a less than 2N DNA content in flow cytometry. Proliferating CML cells were not re…