Search results for "topoi"
showing 10 items of 701 documents
CD133+ bone marrow stem cells (BMSC) control platelet activation – Role of ectoNTPDase-1 (CD39)
2019
Abstract Background We previously demonstrated CD133+ bone marrow stem cells (BMSC) to promote hepatic proliferation for liver regeneration. Here, we evaluated the capacity of CD133+BMSC to utilize platelets for homing to vasculature and concomitant controlling their aggregability upon ADP stimulation. Methods CD133+BMSC and platelets were co-cultured along micro endothelial cells under variable flow conditions and tested for homing levels along vasculature. Aggregometry and FACS analysis were utilized to evaluate platelet reactivity following co-incubation ± CD133+BMSC. RT-PCR and FACS analyses served to characterize ADP degrading ectonucleoside triphosphate diphosphohydrolase-1 (ectoNTPDa…
Definition ofDrosophilahemocyte subsets by cell-type specific antigens
2008
We analyzed the heterogeneity of Drosophila hemocytes on the basis of the expression of cell-type specific antigens. The antigens characterize distinct subsets which partially overlap with those defined by morphological criteria. On the basis of the expression or the lack of expression of blood cell antigens the following hemocyte populations have been defined: crystal cells, plasmatocytes, lamellocytes and precursor cells. The expression of the antigens and thus the different cell types are developmentally regulated. The hemocytes are arranged in four main compartments: the circulating blood cells, the sessile tissue, the lymph glands and the posterior hematopoietic tissue. Each hemocyte c…
Synthesis and Antitumor Properties of 2,5-Bis(3'-indolyl) thiophenes: Analogues of Marine Alkaloid Nortopsentin
2007
A series of 11 bis-indolylthiophenes of formula I were obtained by cyclization of bis-indole 1,4-diketones using Lawesson''s reagent. Derivs. I (R = OMe, R1 = SO2Ph), I (R = OMe, R1 = Me), I (R = Cl, R1 = Me), and I (R = OMe, R1 = H) were selected to be evaluated in the full panel of about 60 human tumor cell lines derived from nine human cancer cell types and showed antiproliferative activity generally in the micromolar range. The most sensitive cell lines were: CCRF-CEM, MOLT-4, HL60 (TB), and RPMI-8226 of the leukemia subpanel, HT29 and HCC-2998 cell lines of the colon sub-panel, NCI-H522 of the non-small cell lung cancer sub-panel, LOX IMVI of the melanoma sub-panel, and UO-31 of the re…
Mast Cell–deficient KitW-sh “Sash” Mutant Mice Display Aberrant Myelopoiesis Leading to the Accumulation of Splenocytes That Act as Myeloid-Derived S…
2013
Abstract Mast cell-deficient KitW-sh “sash” mice are widely used to investigate mast cell functions. However, mutations of c-Kit also affect additional cells of hematopoietic and nonimmune origin. In this study, we demonstrate that KitW-sh causes aberrant extramedullary myelopoiesis characterized by the expansion of immature lineage-negative cells, common myeloid progenitors, and granulocyte/macrophage progenitors in the spleen. A consistent feature shared by these cell types is the reduced expression of c-Kit. Populations expressing intermediate and high levels of Ly6G, a component of the myeloid differentiation Ag Gr-1, are also highly expanded in the spleen of sash mice. These cells are …
Rapid Differentiation of a Rare Subset of Adult Human Lin−CD34−CD38− Cells Stimulated by Multiple Growth Factors In Vitro
1999
Recently, several reports of lineage-negative (lin(-)) CD34(-) cells with in vivo hematopoietic activity have focused interest on the properties and growth factor response characteristics of these cells. We have now identified a combination of 5 growth factors that are necessary and sufficient to stimulate a marked mitogenic and differentiation response by a subset of human lin(-)CD34(-)CD38(-) cells present in normal adult human marrow and granulocyte colony-stimulating factor (G-CSF)-mobilized blood. Less than 0.1% of the cells in highly purified (including doubly sorted) lin(-)CD34(-)CD38(-) cells from these 2 sources formed colonies directly in semisolid medium or generated such cells a…
Candida albicans triggers proliferation and differentiation of hematopoietic stem and progenitor cells by a MyD88-dependent signaling.
2009
As TLRs are expressed by hematopoietic stem and progenitor cells, these receptors may play a role in hematopoiesis in response to pathogens during infection. We showed here that inactivated yeasts and hyphae of Candida albicans induce in vitro the proliferation of purified murine hematopoietic stem and progenitor cells (Lin(-)c-Kit(+) Sca-1(+)) as well as their differentiation to lineage positive cells, through a MyD88-dependent pathway. These results indicate that TLR-mediated recognition of C. albicans by hematopoietic stem and progenitor cells may augment the host capability for rapidly replenishing the innate immune system during candidiasis.
Extramedullary Expansion of Hematopoietic Progenitor Cells in Interleukin (IL)-6–sIL-6R Double Transgenic Mice
1997
Soluble cytokine receptors modulate the activity of their cognate ligands. Interleukin (IL)-6 in association with the soluble IL-6 receptor (sIL-6R) can activate cells expressing the gp130 signal transducer lacking the specific IL-6R. To investigate the function of the IL-6–sIL-6R complex in vivo and to discriminate the function of the IL-6–sIL-6R complex from the function of IL-6 alone, we have established a transgenic mouse model. Double-transgenic mice coexpressing IL-6 and sIL-6R were generated and compared with IL-6 and sIL-6R single-transgenic mice. The main phenotype found in IL-6–sIL-6R mice was a dramatic increase of extramedullary hematopoietic progenitor cells in liver and spleen…
Genetic Cell Ablation Reveals Clusters of Local Self-Renewing Microglia in the Mammalian Central Nervous System
2015
SummaryDuring early embryogenesis, microglia arise from yolk sac progenitors that populate the developing central nervous system (CNS), but how the tissue-resident macrophages are maintained throughout the organism’s lifespan still remains unclear. Here, we describe a system that allows specific, conditional ablation of microglia in adult mice. We found that the microglial compartment was reconstituted within 1 week of depletion. Microglia repopulation relied on CNS-resident cells, independent from bone-marrow-derived precursors. During repopulation, microglia formed clusters of highly proliferative cells that migrated apart once steady state was achieved. Proliferating microglia expressed …
Hyper-IL-6 (H-IL-6), a Fusion Protein of Soluble IL-6 Receptor (Sil-6R), and Interleukin-6 (IL-6), Acts Synergistic with Thrombopoietin (TPO) and Ste…
1999
It has been shown that signalings from c-kit and gpl30, the signal-transducing receptor component of the IL6 receptor, act synergistic for the ex-vivo expansion of multipotential hematopoietic progenitors. A similar synergistic effect has been demonstrated for signalings from c-kit, c-mpl, and flt3. While c-kit is activated by stem cell factor (SCF), gpl30 can be activated by the complex of soluble IL-6 receptor (sIL-6R) and interleukin-6 (IL-6). Recently, a bioactive designer cytokine, H-IL-6, a fusion protein consisting of SIL-6R and IL-6 linked by a flexible peptide chain has been shown to expand human hematopoietic colony-forming cells. We tested the activity of H-IL-6 alone and in comb…
Stress response in mesoangioblast stem cells
2006
Stem cells are presumed to survive various stresses, since they are recruited to areas of tissue damage and regeneration, where inflammatory cytokines and cytotoxic cells may result in severe cell injury. We explored the ability of mesoangioblasts to respond to different cell stresses such as heat, heavy metals and osmotic stress, by analyzing heat shock protein (HSP)70 synthesis as a stress indicator. We found that the A6 mesoangioblast stem cells constitutively synthesize HSP70 in a heat shock transcription factor (HSF)-independent way. However, A6 respond to heat shock and cadmium treatment by synthesizing HSP70 over the constitutive expression and this synthesis is HSF1 dependent. The e…