Publications by authors named "Ornella Morsilli"

15 Publications

  • Page 1 of 1

Platelet and megakaryocyte CD40L expression in β-Thalassemic patients.

Thromb Res 2020 05 2;189:108-111. Epub 2020 Mar 2.

Department of Cardiovascular, Endocrine-Metabolic Diseases and Ageing, Istituto Superiore di Sanità, Rome, Italy. Electronic address:

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http://dx.doi.org/10.1016/j.thromres.2020.02.026DOI Listing
May 2020

From Human Megakaryocytes to Platelets: Effects of Aspirin on High-Mobility Group Box 1/Receptor for Advanced Glycation End Products Axis.

Front Immunol 2017 12;8:1946. Epub 2018 Jan 12.

Department of Experimental Medicine, University of Rome Sapienza, Rome, Italy.

Platelets (PLTs) are the major source of high-mobility group box 1 (HMGB1), a protein that is involved in sterile inflammation of blood vessels and thrombosis. Megakaryocytes (MKs) synthesize HMGB1 and transfer both protein and mRNA into PLTs and PLT-derived microvesicles (MV). Free HMGB1 found in supernatants of differentiated MKs and in a megakaryoblastic cell line (DAMI cells). Aspirin "" and "" not only reduces HMGB1 and receptor for advanced glycation end products expression on MKs and PLTs but also drives the movement of HMGB1 from MKs into PLTs and PLT-derived MV. These findings suggest that consumption of low doses of aspirin reduces the risk of atherosclerosis complications as well as reducing PLT aggregation by the inhibition of COX-1.
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http://dx.doi.org/10.3389/fimmu.2017.01946DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5770369PMC
January 2018

SCF-mediated γ-globin gene expression in adult human erythroid cells is associated with KLF1, BCL11A and SOX6 down-regulation.

Blood Cells Mol Dis 2015 Jan 3;54(1):1-3. Epub 2014 Nov 3.

Dept. of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy. Electronic address:

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http://dx.doi.org/10.1016/j.bcmd.2014.10.004DOI Listing
January 2015

HOXB1 restored expression promotes apoptosis and differentiation in the HL60 leukemic cell line.

Cancer Cell Int 2013 Oct 22;13(1):101. Epub 2013 Oct 22.

Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore Sanità, Rome 00161, Italy.

Background: Homeobox (HOX) genes deregulation has been largely implicated in the development of human leukemia. Among the HOXB cluster, HOXB1 was silent in a number of analyzed acute myeloid leukemia (AML) primary cells and cell lines, whereas it was expressed in normal terminally differentiated peripheral blood cells.

Methods: We evaluated the biological effects and the transcriptome changes determined by the retroviral transduction of HOXB1 in the human promyelocytic cell line HL60.

Results: Our results suggest that the enforced expression of HOXB1 reduces cell growth proliferation, inducing apoptosis and cell differentiation along the monocytic and granulocytic lineages. Accordingly, gene expression analysis showed the HOXB1-dependent down-regulation of some tumor promoting genes, paralleled by the up-regulation of apoptosis- and differentiation-related genes, thus supporting a tumor suppressor role for HOXB1 in AML. Finally, we indicated HOXB1 promoter hypermethylation as a mechanism responsible for HOXB1 silencing.

Conclusions: We propose HOXB1 as an additional member of the HOX family with tumour suppressor properties suggesting a HOXB1/ATRA combination as a possible future therapeutic strategy in AML.
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http://dx.doi.org/10.1186/1475-2867-13-101DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3874656PMC
October 2013

MicroRNA-486-3p regulates γ-globin expression in human erythroid cells by directly modulating BCL11A.

PLoS One 2013 4;8(4):e60436. Epub 2013 Apr 4.

Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.

MicroRNAs (miRNAs) play key roles in modulating a variety of cellular processes through repression of mRNAs target. The functional relevance of microRNAs has been proven in normal and malignant hematopoiesis. While analyzing miRNAs expression profile in unilineage serum-free liquid suspension unilineage cultures of peripheral blood CD34(+) hematopoietic progenitor cells (HPCs) through the erythroid, megakaryocytic, granulocytic and monocytic pathways, we identified miR-486-3p as mainly expressed within the erythroid lineage. We showed that miR-486-3p regulates BCL11A expression by binding to the extra-long isoform of BCL11A 3'UTR. Overexpression of miR-486-3p in erythroid cells resulted in reduced BCL11A protein levels, associated to increased expression of γ-globin gene, whereas inhibition of physiological miR-486-3p levels increased BCL11A and, consequently, reduced γ-globin expression. Thus, miR-486-3p regulating BCL11A expression might contributes to fetal hemoglobin (HbF) modulation and arise the question as to what extent this miRNA might contribute to different HbF levels observed among β-thalassemia patients. Erythroid cells, differentiated from PB CD34(+) cells of a small cohort of patients affected by major or intermedia β-thalassemia, showed miR-486-3p levels significantly higher than those observed in normal counterpart. Importantly, in these patients, miR-486-3p expression correlates with increased HbF synthesis. Thus, our data indicate that miR-486-3p might contribute to different HbF levels observed among thalassemic patients and, possibly, to the clinical severity of the disease.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0060436PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3617093PMC
November 2013

Autocrine role of angiopoietins during megakaryocytic differentiation.

PLoS One 2012 6;7(7):e39796. Epub 2012 Jul 6.

Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.

The tyrosine kinase Tie-2 and its ligands Angiopoietins (Angs) transduce critical signals for angiogenesis in endothelial cells. This receptor and Ang-1 are coexpressed in hematopoietic stem cells and in a subset of megakaryocytes, though a possible role of angiopoietins in megakaryocytic differentiation/proliferation remains to be demonstrated. To investigate a possible effect of Ang-1/Ang-2 on megakaryocytic proliferation/differentiation we have used both normal CD34(+) cells induced to megakaryocytic differentiation and the UT7 cells engineered to express the thrombopoietin receptor (TPOR, also known as c-mpl, UT7/mpl). Our results indicate that Ang-1/Ang-2 may have a role in megakaryopoiesis. Particularly, Ang-2 is predominantly produced and released by immature normal megakaryocytic cells and by undifferentiated UT7/mpl cells and slightly stimulated TPO-induced cell proliferation. Ang-1 production is markedly induced during megakaryocytic differentiation/maturation and potentiated TPO-driven megakaryocytic differentiation. Blocking endogenously released angiopoietins partially inhibited megakaryocytic differentiation, particularly for that concerns the process of polyploidization. According to these data it is suggested that an autocrine angiopoietin/Tie-2 loop controls megakaryocytic proliferation and differentiation.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0039796PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3391299PMC
March 2013

Mechanism of human Hb switching: a possible role of the kit receptor/miR 221-222 complex.

Haematologica 2010 Aug 19;95(8):1253-60. Epub 2010 Mar 19.

Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, 00161 Rome, Italy.

Background: The human hemoglobin switch (HbF-->HbA) takes place in the peri/post-natal period. In adult life, however, the residual HbF (<1%) may be partially reactivated by chemical inducers and/or cytokines such as the kit ligand (KL). MicroRNAs (miRs) play a pivotal role in normal hematopoiesis: downmodulation of miR-221/222 stimulates human erythropoietic proliferation through upmodulation of the kit receptor.

Design And Methods: We have explored the possible role of kit/KL in perinatal Hb switching by evaluating: i) the expression levels of both kit and kit ligand on CD34(+) cells and in plasma isolated from pre-, mid- and full-term cord blood samples; ii) the reactivation of HbF synthesis in KL-treated unilineage erythroid cell cultures; iii) the functional role of miR-221/222 in HbF production.

Results: In perinatal life, kit expression showed a gradual decline directly correlated to the decrease of HbF (from 80-90% to <30%). Moreover, in full-term cord blood erythroid cultures, kit ligand induced a marked increase of HbF (up to 80%) specifically abrogated by addition of the kit inhibitor imatinib, thus reversing the Hb switch. MiR-221/222 expression exhibited rising levels during peri/post-natal development. In functional studies, overexpression of these miRs in cord blood progenitors caused a remarkable decrease in kit expression, erythroblast proliferation and HbF content, whereas their suppression induced opposite effects.

Conclusions: Our studies indicate that human perinatal Hb switching is under control of the kit receptor/miR 221-222 complex. We do not exclude, however, that other mechanisms (i.e. glucocorticoids and the HbF inhibitor BCL11A) may also contribute to the peri/post-natal Hb switch.
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http://dx.doi.org/10.3324/haematol.2009.018259DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2913072PMC
August 2010

NFI-A directs the fate of hematopoietic progenitors to the erythroid or granulocytic lineage and controls beta-globin and G-CSF receptor expression.

Blood 2009 Aug 19;114(9):1753-63. Epub 2009 Jun 19.

Department of Histology and Medical Embryology, University La Sapienza, Rome, Italy.

It is generally conceded that selective combinations of transcription factors determine hematopoietic lineage commitment and differentiation. Here we show that in normal human hematopoiesis the transcription factor nuclear factor I-A (NFI-A) exhibits a marked lineage-specific expression pattern: it is upmodulated in the erythroid (E) lineage while fully suppressed in the granulopoietic (G) series. In unilineage E culture of hematopoietic progenitor cells (HPCs), NFI-A overexpression or knockdown accelerates or blocks erythropoiesis, respectively: notably, NFI-A overexpression restores E differentiation in the presence of low or minimal erythropoietin stimulus. Conversely, NFI-A ectopic expression in unilineage G culture induces a sharp inhibition of granulopoiesis. Finally, in bilineage E + G culture, NFI-A overexpression or suppression drives HPCs into the E or G differentiation pathways, respectively. These NFI-A actions are mediated, at least in part, by a dual and opposite transcriptional action: direct binding and activation or repression of the promoters of the beta-globin and G-CSF receptor gene, respectively. Altogether, these results indicate that, in early hematopoiesis, the NFI-A expression level acts as a novel factor channeling HPCs into either the E or G lineage.
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http://dx.doi.org/10.1182/blood-2008-12-196196DOI Listing
August 2009

MicroRNA 223-dependent expression of LMO2 regulates normal erythropoiesis.

Haematologica 2009 Apr 10;94(4):479-86. Epub 2009 Mar 10.

Dept. of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.

Background: MicroRNAs are small non-coding RNAs that regulate gene expression through mRNA degradation or translational inhibition. MicroRNAs are emerging as key regulators of normal hematopoiesis and hematologic malignancies. Several miRNAs are differentially expressed during hematopoiesis and their specific expression regulates key functional proteins involved in hematopoietic lineage differentiation. This study focused on the functional role of microRNA-223 (miR-223) on erythroid differentiation.

Design And Methods: Purified cord blood CD34+ hematopoietic progenitor cells were grown in strictly controlled conditions in the presence of saturating dosage of erythropoietin to selectively induce erythroid differentiation. The effects of enforced expression of miR-223 in unilin-eage erythroid cultures were evaluated in liquid phase culture experiments and clonogenic studies.

Results: In unilineage erythroid culture of cord blood CD34+ hematopoietic progenitor cells miR-223 is down-regulated, whereas LMO2, an essential protein for erythroid differentiation, is up-regulated. Functional studies showed that enforced expression of miR-223 reduces the mRNA and protein levels of LMO2, by binding to LMO2 3' UTR, and impairs differentiation of erythroid cells. Accordingly, knockdown of LMO2 by short interfering RNA mimics the action of miR-223. Furthermore, hematopoietic progenitor cells transduced with miR-223 showed a significant reduction of their erythroid clonogenic capacity, suggesting that downmodulation of this miRNA is required for erythroid progenitor recruitment and commitment.

Conclusions: These results show that the decline of miR-223 is an important event for erythroid differentiation that leads to the expansion of erythroblast cells at least partially mediated by unblocking LMO2 protein expression.
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http://dx.doi.org/10.3324/haematol.2008.002345DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2663611PMC
April 2009

Effective erythropoiesis and HbF reactivation induced by kit ligand in beta-thalassemia.

Blood 2008 Jan 19;111(1):421-9. Epub 2007 Oct 19.

Department of Hematology, Oncology, and Molecular Medicine, Istituto Superiore di Sanità, Viale Regina Elena, 299-00161 Rome, Italy.

In human beta-thalassemia, the imbalance between alpha- and non-alpha-globin chains causes ineffective erythropoiesis, hemolysis, and anemia: this condition is effectively treated by an enhanced level of fetal hemoglobin (HbF). In spite of extensive studies on pharmacologic induction of HbF synthesis, clinical trials based on HbF reactivation in beta-thalassemia produced inconsistent results. Here, we investigated the in vitro response of beta-thalassemic erythroid progenitors to kit ligand (KL) in terms of HbF reactivation, stimulation of effective erythropoiesis, and inhibition of apoptosis. In unilineage erythroid cultures of 20 patients with intermedia or major beta-thalassemia, addition of KL, alone or combined with dexamethasone (Dex), remarkably stimulated cell proliferation (3-4 logs more than control cultures), while decreasing the percentage of apoptotic and dyserythropoietic cells (<5%). More important, in both thalassemic groups, addition of KL or KL plus Dex induced a marked increase of gamma-globin synthesis, thus reaching HbF levels 3-fold higher than in con-trol cultures (eg, from 27% to 75% or 81%, respectively, in beta-thalassemia major). These studies indicate that in beta-thalassemia, KL, alone or combined with Dex, induces an expansion of effective erythropoiesis and the reactivation of gamma-globin genes up to fetal levels and may hence be considered as a potential therapeutic agent for this disease.
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http://dx.doi.org/10.1182/blood-2007-06-097550DOI Listing
January 2008

MicroRNAs 221 and 222 inhibit normal erythropoiesis and erythroleukemic cell growth via kit receptor down-modulation.

Proc Natl Acad Sci U S A 2005 Dec 5;102(50):18081-6. Epub 2005 Dec 5.

Department of Hematology, Oncology, and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.

MicroRNAs (miRs) are small noncoding RNAs that regulate gene expression primarily through translational repression. In erythropoietic (E) culture of cord blood CD34+ progenitor cells, the level of miR 221 and 222 is gradually and sharply down-modulated. Hypothetically, this decline could promote erythropoiesis by unblocking expression of key functional proteins. Indeed, (i) bioinformatic analysis suggested that miR 221 and 222 target the 3' UTR of kit mRNA; (ii) the luciferase assay confirmed that both miRs directly interact with the kit mRNA target site; and (iii) in E culture undergoing exponential cell growth, miR down-modulation is inversely related to increasing kit protein expression, whereas the kit mRNA level is relatively stable. Functional studies show that treatment of CD34+ progenitors with miR 221 and 222, via oligonucleotide transfection or lentiviral vector infection, causes impaired proliferation and accelerated differentiation of E cells, coupled with down-modulation of kit protein: this phenomenon, observed in E culture releasing endogenous kit ligand, is magnified in E culture supplemented with kit ligand. Furthermore, transplantation experiments in NOD-SCID mice reveal that miR 221 and 222 treatment of CD34+ cells impairs their engraftment capacity and stem cell activity. Finally, miR 221 and 222 gene transfer impairs proliferation of the kit+ TF-1 erythroleukemic cell line. Altogether, our studies indicate that the decline of miR 221 and 222 during exponential E growth unblocks kit protein production at mRNA level, thus leading to expansion of early erythroblasts. Furthermore, the results on kit+ erythroleukemic cells suggest a potential role of these miRs in cancer therapy.
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http://dx.doi.org/10.1073/pnas.0506216102DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1312381PMC
December 2005

Expression of alternative transcripts of ferroportin-1 during human erythroid differentiation.

Haematologica 2005 Dec;90(12):1595-606

Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.

Background And Objectives: Ferroportin-1 (FPN1) is expressed in various types of cells that play critical roles in mammalian iron metabolism and appears to act as an iron exporter in these tissues. The aim of this study was to investigate whether erythroid cells possess specific mechanisms for iron export.

Design And Methods: The expression of FPN1 during human erythroid differentiation, the characterization of alternative transcripts, the modulation by iron and the subcellular localization of this protein were studied.

Results: FPN1 mRNA and protein are highly expressed during human erythroid differentiation. The iron-responsive element (IRE) in the 5'- untranslated region (UTR) of FPN1 mRNA is functional but, in spite of that, FPN1 protein expression, as well as mRNA level and half-life, seem not to be affected by iron. To explain these apparenthy discordant results we searched for alternative transcripts of FPN1 and found at least three different types of transcripts, displaying alternative 5' ends. Most of the FPN1 transcripts code for the canonical protein, but only half of them contain an IRE in the 5'-UTR and have the potential to be translationally regulated by iron. Expression analysis shows that alternative FPN1 transcripts are differentially expressed during erythroid differentiation. Finally, sustained expression of alternative FPN1 transcripts is apparently observed only in erythroid cells.

Interpretation And Conclusions: This is the first report describing the presence of FPN1 in erythroid cells at all stages of differentiation, providing evidence that erythroid cells possess specific mechanisms of iron export. The existence of multiple FPN1 transcripts indicates a complex regulation of the FPN1 gene in erythroid cells.
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December 2005

Transferrin receptor 2 protein is not expressed in normal erythroid cells.

Biochem J 2004 Aug;381(Pt 3):629-34

Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.

Human TFR2 (transferrin receptor 2) is a membrane-bound protein homologous with TFR1. High levels of TFR2 mRNA were found mainly in the liver and, to a lesser extent, in erythroid precursors. However, although the presence of the TFR2 protein in hepatic cells has been confirmed in several studies, evidence is lacking about the presence of the TFR2 protein in normal erythroid cells. Using two anti-TFR2 monoclonal antibodies, G/14C2 and G/14E8, we have provided evidence that TFR2 protein is not expressed in normal erythroid cells at any stage of differentiation, from undifferentiated CD34+ cells to mature orthochromatic erythroblasts. In contrast, erythroleukaemic cells (K562 cells) exhibited a high level of expression of TFR2 at both the mRNA and the protein level. We can therefore conclude that an elevated expression of TFR2 protein is observed in leukaemic cells, but not in normal erythroblasts. The implications of this observation for the understanding of the phenotypic features of haemochromatosis due to mutation of the TFR2 gene are discussed.
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http://dx.doi.org/10.1042/BJ20040230DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1133871PMC
August 2004

HbF reactivation in sibling BFU-E colonies: synergistic interaction of kit ligand with low-dose dexamethasone.

Blood 2003 Apr 7;101(7):2826-32. Epub 2002 Nov 7.

Department of Hematology and Oncology, Istituto Superiore di Sanità, Rome, Italy.

Mechanisms underlying fetal hemoglobin (HbF) reactivation in stress erythropoiesis have not been fully elucidated. We suggested that a key role is played by kit ligand (KL). Because glucocorticoids (GCs) mediate stress erythropoiesis, we explored their capacity to potentiate the stimulatory effect of KL on HbF reactivation, as evaluated in unilineage erythropoietic culture of purified adult progenitors (erythroid burst-forming units [BFU-Es]). The GC derivative dexamethasone (Dex) was tested in minibulk cultures at graded dosages within the therapeutical range (10(-6) to 10(-9) M). Dex did not exert significant effects alone, but synergistically it potentiated the action of KL in a dose-dependent fashion. Specifically, Dex induced delayed erythroid maturation coupled with a 2-log increased number of generated erythroblasts and enhanced HbF synthesis up to 85% F cells and 55% gamma-globin content at terminal maturation (ie, in more than 80%-90% mature erythroblasts). Equivalent results were obtained in unicellular erythroid cultures of sibling BFU-Es treated with KL alone or combined with graded amounts of Dex. These results indicate that the stimulatory effect of KL + Dex is related to the modulation of gamma-globin expression rather than to recruitment of BFU-Es with elevated HbF synthetic potential. At the molecular level, Id2 expression is totally suppressed in control erythroid culture but is sustained in KL + Dex culture. Hypothetically, Id2 may mediate the expansion of early erythroid cells, which correlates with HbF reactivation. These studies indicate that GCs play an important role in HbF reactivation. Because Dex acts at dosages used in immunologic disease therapy, KL + Dex administration may be considered to develop preclinical models for beta-hemoglobinopathy treatment.
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http://dx.doi.org/10.1182/blood-2002-05-1477DOI Listing
April 2003

Autocrine-paracrine VEGF loops potentiate the maturation of megakaryocytic precursors through Flt1 receptor.

Blood 2003 Feb 24;101(4):1316-23. Epub 2002 Oct 24.

Department of Hematology-Oncology, Istituto Superiore di Sanità, Rome, Italy.

The expression/function of vascular endothelial growth factor (VEGF) receptors (VEGFR1/Flt1 and VEGFR2/KDR/Flk1) in hematopoiesis is under scrutiny. We have investigated the expression of Flt1 and kinase domain receptor (KDR) on hematopoietic precursors, as evaluated in liquid culture of CD34(+) hematopoietic progenitor cells (HPCs) induced to unilineage differentiation/maturation through the erythroid (E), megakaryocytic (Mk), granulocytic (G), or monocytic (Mo) lineage. KDR, expressed on 0.5% to 1.5% CD34(+) cells, is rapidly downmodulated on induction of differentiation. Similarly, Flt1 is present at very low levels in HPCs and is downmodulated in E and G lineages; however, Flt1 is induced in the precursors of both Mo and Mk series; ie, its level progressively increases during Mo maturation, and it peaks at the initial-intermediate culture stages in the Mk lineage. Functional experiments indicate that Mk and E, but not G and Mo, precursors release significant amounts of VEGF in the culture medium, particularly at low O(2) levels. The functional role of VEGF release on Mk maturation is indicated by 2 series of observations. (1) Molecules preventing the VEGF-Flt1 interaction on the precursor membrane (eg, soluble Flt1 receptors) significantly inhibit Mk polyploidization. (2) Addition of exogenous VEGF or placenta growth factor (PlGF) markedly potentiates Mk maturation. Conversely, VEGF does not modify Mo differentiation/maturation. Altogether, our results suggest that in the hematopoietic microenvironment an autocrine VEGF loop contributes to optimal Mk maturation through Flt1. A paracrine loop involving VEGF release by E precursors may also operate. Similarly, recent studies indicate that an autocrine loop involving VEGF and Flt1/Flk1 receptors mediates hematopoietic stem cell survival and differentiation.
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http://dx.doi.org/10.1182/blood-2002-07-2184DOI Listing
February 2003