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Erythroid Progenitors (erythroid + progenitor)
Terms modified by Erythroid Progenitors Selected AbstractsCombined effect of IL-17 and blockade of nitric oxide biosynthesis on haematopoiesis in miceACTA PHYSIOLOGICA, Issue 1 2010A. Krsti Abstract Aim:, The study was undertaken to extend our investigation concerning both the in vivo activity of interleukin (IL)-17 and the specific role of nitric oxide (NO) in IL-17-induced effects in the process of haematopoiesis. Methods:, CBA mice were simultaneously treated with IL-17 and/or nitric oxide synthase (NOS) inhibitor, l -NAME, for 5 days and changes within various haematopoietic cell lineages in bone marrow, spleen and peripheral blood were analysed. Results:, Findings showed that administration of both IL-17 and l -NAME stimulated increase in net haematopoiesis in normal mice. IL-17-enhanced myelopoiesis was characterized by stimulation of both femoral and splenic haematopoietic progenitor cells and morphologically recognizable granulocytes. Additionally, IL-17 induced alterations in the frequency of erythroid progenitor cells in both bone marrow and spleen, accompanied with their mobilization to the peripheral blood. As a consequence of these changes in the erythroid cell compartments, significant reticulocytosis was observed, which evidenced that in IL-17-treated mice effective erythropoiesis occurred. Exposure of mice to NOS inhibitor also increased the number of both granulocyte-macrophage and erythroid progenitors in bone marrow and spleens, and these alterations were followed by the mobilization of erythroid progenitors and elevated content of reticulocytes in peripheral blood. The specific role of NO in IL-17-induced haematopoiesis was demonstrated only in the IL-17-reducing effect on bone marrow late stage erythroid progenitors, CFU-E. Conclusion:, The results demonstrated the involvement of both IL-17 and NO in the regulation of haematopoietic cell activity in various haematopoietic compartments. They further suggest that IL-17 effects are differentially mediated depending on the haematopoietic microenvironments. [source] Effects of rapamycin on accumulation of , -, , - and , -globin mRNAs in erythroid precursor cells from , -thalassaemia patientsEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 5 2006Eitan Fibach Abstract:, We studied the effects of rapamycin on cultures of erythroid progenitors derived from the peripheral blood of 10 , -thalassaemia patients differing widely with respect to their potential to produce foetal haemoglobin (HbF). For this, we employed the two-phase liquid culture procedure for growing erythroid progenitors, high performance liquid chromatography for analysis of HbF production and reverse transcription polymerase chain reaction for quantification of the accumulation of globin mRNAs. The results demonstrated that rapamycin induced an increase of HbF in cultures from all the , -thalassaemia patients studied and an increase of their overall Hb content/cell. The inducing effect of rapamycin was restricted to , -globin mRNA accumulation, being only minor for , -globin and none for , -globin mRNAs. The ability of rapamycin to preferentially increase , -globin mRNA content and production of HbF in erythroid precursor cells from , -thalassaemia patients is of great importance as this agent (also known as sirolimus or rapamune) is already in clinical use as an anti-rejection agent following kidney transplantation. These data suggest that rapamycin warrants further evaluation as a potential therapeutic drug in , -thalassaemia and sickle cell anaemia. [source] RANK Expression as a Cell Surface Marker of Human Osteoclast Precursors in Peripheral Blood, Bone Marrow, and Giant Cell Tumors of BoneJOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2006Gerald J Atkins Abstract RANK expression in vivo on hematopoietic subsets including pre-osteoclasts, identified by monoclonal antibodies, has not been described. We describe the lineages that express RANK in bone marrow, peripheral blood, and GCTs. We show that CD14+RANKhigh cells constitute a circulating pre-osteoclast pool. Introduction: The expression of RANK by subsets of hematopoietic cells has not been adequately studied in humans. While attributed to the monocytoid lineage, the phenotype of the pre-osteoclast (pre-OC) with respect to RANK expression in vivo remains unclear. We tested monoclonal antibodies (MAbs) raised against the extracellular domain of recombinant human RANK for reactivity with normal peripheral blood (PB) and bone marrow (BM) mononuclear cells (PBMNCs and BMMNCs, respectively). We also tested reactivity with giant cell tumor cells (GCT), a confirmed source of pre-OC and mature OCs. Materials and Methods: Human PBMNCs, BMMNCs, and GCT cells were analyzed for reactivity with anti-RANK MAbs by flow cytometry in combination with hematopoietic lineage restricted markers. GCTs were also analyzed by immunofluorescence. CD14+ monocytoid cells were sorted by fluorescence-activated cell sorting (FACS) based on their relative RANK expression and cultured under OC-forming conditions. Results: RANK+ cells were detected similarly by three independent anti-RANK MAbs. One MAb (80736) immunoprecipitated RANK,RANKL complexes from surface-biotinylated GCT lysates. Using dual-color flow cytometry, RANK was detected on CD14+ (monocytoid), CD19+ (B-lymphoid), CD56+ (NK cell), and glycophorin A+ erythroid progenitors. Minor populations of both CD3+ T lymphocytes and BM CD34+ hematopoietic progenitors also expressed cell surface RANK. In GCTs, RANK expression was identified on mononuclear CD45+CD14+,V,3+c-Fms+ cells, likely to be committed pre-OC, and on multinucleated CD45+,V,3+TRACP+ OCs. Importantly, sorted CD14+RANKhigh PBMNCs treated with recombinant RANKL and macrophage-colony stimulating factor (M-CSF) gave rise to approximately twice the number of osteoclasts than RANKmid or RANKlow cells. Conclusions: These results suggest that committed monocytoid RANK+ pre-OCs are represented in the marrow and circulate in the periphery, forming a pool of cells capable of responding rapidly to RANKL. The ability to reliably detect committed pre-OC in peripheral blood could have important clinical applications in the management of diseases characterized by abnormal osteoclastic activity. [source] A ,bottom-up' approach for endo-PK/PD analysisBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 7 2006S. Neelakantan Abstract A ,bottom-up' PK/PD analysis approach employing system analysis principles of convolution/deconvolution and special nonparametric estimation procedures is presented to resolve the complex ,endo-PK/PD' of the endogenous form of recombinant drugs using erythropoietin (EPO) as an example. A novel cellular deconvolution algorithm is presented that facilitates the identification of the functional relationship between the variables involved in EPO's complex PK/PD. Five sheep each underwent two phlebotomies spaced 4,6 weeks apart when their hemoglobin levels were reduced from 12 g/dl to 3,4 g/dl. EPO levels and reticulocyte counts were frequently sampled. The data were analysed using end-constrained cubic splines. The rate of reticulocyte production was determined using the novel deconvolution methodology. The erythroid progenitor cells activation rate by EPO was estimated from the reticulocyte production rate using a lag-time parameter which determines the delay in the reticulocyte appearance in the blood relative to the activation of erythroid progenitors. Hysteresis minimization combined with cellular deconvolution was employed to determine the population PK/PD transduction function relating the progenitor activation rate to EPO concentrations in a nonparametric manner without assuming a specific structure. The proposed approach provides a rational informative starting point for developing parametric PK/PD models to resolve the complex endo-PK/PD of recombinant drugs. Copyright © 2006 John Wiley & Sons, Ltd. [source] The JAK kinase inhibitor CP-690,550 supresses the growth of human polycythemia vera cells carrying the JAK2V617F mutationCANCER SCIENCE, Issue 6 2008Taghi Manshouri The somatic activating janus kinase 2 mutation (JAK2)V617F is detectable in most patients with polycythemia vera (PV). Here we report that CP-690,550 exerts greater antiproliferative and pro-apoptotic activity against cells harboring JAK2V617F compared with JAK2WT. CP-690,550 treatment of murine factor-dependent cell Patersen,erythropoietin receptor (FDCP-EpoR) cells harboring human wild-type or V617F JAK2 resulted in inhibition of cell proliferation with a 50% inhibitory concentration (IC50) of 2.1 µM and 0.25 µM, respectively. Moreover, CP-690,550 induced a significant pro-apoptotic effect on murine FDCP-EpoR cells carrying JAK2V617F, whereas a lesser effect was observed for cells carrying wild-type JAK2. This activity was coupled with inhibition of phosphorylation of the key JAK2V617F -dependent downstream signaling effectors signal transducer and activator of transcription (STAT)3, STAT5, and v-akt murine thymoma viral oncogene homolog (AKT). Furthermore, CP-690,550 treatment of ex-vivo -expanded erythroid progenitors from JAK2V617F -positive PV patients resulted in specific, antiproliferative (IC50 = 0.2 µM) and pro-apoptotic activity. In contrast, expanded progenitors from healthy controls were less sensitive to CP-690,550 in proliferation (IC50 > 1.0 µM), and apoptosis assays. The antiproliferative effect on expanded patient progenitors was paralleled by a decrease in JAK2V617F mutant allele frequency, particularly in a patient homozygous for JAK2V617F. Flow cytometric analysis of expanded PV progenitor cells treated with CP-690,550 suggests a possible transition towards a pattern of erythroid differentiation resembling expanded cells from normal healthy controls. (Cancer Sci 2008; 99: 1265,1273) [source] Stem cell antigen 2: a new gene involved in the self-renewal of erythroid progenitorsCELL PROLIFERATION, Issue 5 2008C. Bresson-Mazet We have previously shown that SCA2 is overexpressed in self-renewing avian erythroid progenitors (T2ECs) as opposed to differentiating T2ECs. The aim of this study was to define the role of SCA2 in the switch between self-renewal and differentiation of erythroid progenitors. Materials and methods: We have investigated the cellular processes controlled by SCA2 in T2ECs by RNA interference and overexpression approaches. Moreover, we have used a SAGE Querying and analysis tools developed in our laboratory, to investigate the expression level of SCA2 gene in different human cell types. Results: We demonstrate the regulation of SCA2 expression by TGF-,, a growth factor essential for self-renewal of T2ECs. We establish that SCA2 knockdown by RNA interference reduced the proliferation and promoted the differentiation of T2ECs. In contrast, SCA2 overexpression inhibited differentiation of T2ECs only. Furthermore, by using a bioinformatic approach, we found that SCA2 is highly expressed in a variety of human cancer cells. We confirmed this result by quantitative PCR on human colon and kidney tissues. Conclusions: Altogether, these findings imply that SCA2 may function in a dose-dependent manner to support the self-renewal state and that its deregulation might contribute to the development of some human cancers. [source] | |||||||||||||