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Myeloid Cells (myeloid + cell)

Distribution by Scientific Domains
Medical Sciences67%
Life Sciences25%
Chemistry6%
Distribution within Medical Sciences
Hematology22%
13 Other Subdomains56%

Kinds of Myeloid Cells

  • immature myeloid cell
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    Terms modified by Myeloid Cells

  • myeloid cell line
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    Selected Abstracts

    Fc, receptor I activation induces leukocyte recruitment and promotes aggravation of glomerulonephritis through the FcR, adaptor

    EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2007
    Yutaka Kanamaru
    Abstract Myeloid cells bear Fc receptors (FcR) that mediate inflammatory signaling through the ITAM-containing FcR, adaptor. They express FcR,-associated Fc,RI, which modulate either activating or inhibitory signaling depending on the type of ligand interaction. The role of Fc,RI, in disease progression remains unknown, notably in IgA nephropathy (IgAN), one of major causes of end-stage renal disease, in which large amounts of circulating IgA-immune complexes (IC) may mediate receptor activation. To analyze the involvement of Fc,RI activation in glomerulonephritis (GN), we generated Tg mice expressing a mutated, signaling-incompetent, human Fc,RIR209L that cannot associate with FcR,. Like Fc,RIwt -Tg mice, they developed mesangial IgA deposits but not macrophage infiltration. Fc,RI activation in Fc,RIwt, but not in Fc,RIR209L, Tg mice resulted in marked inflammation with severe proteinuria and leukocyte infiltration in spontaneous IgAN or anti-glomerular basement membrane Ab-induced GN models. Receptor triggering of syngenically transferred Fc,RIwt Tg macrophages into non-Tg animals induced their recruitment into injured kidneys during GN development. Fc,RIwt cross-linking on macrophages activated MAP kinases and production of TNF-, and MCP-1. Moreover, IgA-IC from IgAN patients activated Fc,RI and induced TNF-, production. Thus, Fc,RI activation mediates GN progression by initiating a cytokine/chemokine cascade that promotes leukocyte recruitment and kidney damage. [source]

    4255: Integrating the interplay between innate and adaptive immunity in the development of non infectious uveitis

    ACTA OPHTHALMOLOGICA, Issue 2010
    AD DICK
    Purpose Whilst uveitis is a CD4 T cell mediated disease, there remains both the interplay with innate immunity at both the affector (initiation) of disease and moreso the phenotype and severity of the effector stages of disease. Methods The talk will describe the experimental evidence to describe the interplay of T cells and myeloid cells within the retina during intraocular inflammation. Results TNF, whilst a pleitropic cytokine, has significant influence of the disease phenotype and disease course we observe experimentally. TNF is requred for activation of myeloid cells (macrophages)when in presence of Th1 CD4 T cells, which results in contribution to tissue damage but also controlling T cell proliferation in situ via generation of myeloid suppressor cells. Moreover, the role of resident myeloid cells (microglia) is to down-regulate the immune response. The role of myeloid cells in the healing response and angiogenesis will also be discussed with respect to T cell responses. Conclusion Myeloid cells are actively conditioned by their envirnoment (cognate and soluble factors) to respond accordingly. As such the regulation of immune response and healing that follows is dictated by the innate system in response to changes in local and systemic conditions. [source]

    Dissociation between liver inflammation and hepatocellular damage induced by carbon tetrachloride in myeloid cell,specific signal transducer and activator of transcription 3 gene knockout mice,

    HEPATOLOGY, Issue 5 2010
    Norio Horiguchi
    Liver injury is associated with inflammation, which is generally believed to accelerate the progression of liver diseases; however, clinical data show that inflammation does not always correlate with hepatocelluar damage in some patients. Investigating the cellular mechanisms underlying these events using an experimental animal model, we show that inflammation may attenuate liver necrosis induced by carbon tetrachloride (CCl4) in myeloid-specific signal transducer and activator of transcription 3 (STAT3) knockout mice. As an important anti-inflammatory signal, conditional deletion of STAT3 in myeloid cells results in markedly enhanced liver inflammation after CCl4 injection. However, these effects are also accompanied by reduced liver necrosis, correlating with elevated serum interleukin-6 (IL-6) and hepatic STAT3 activation. An additional deletion of STAT3 in hepatocytes in myeloid-specific STAT3 knockout mice restored hepatic necrosis but decreased liver inflammation. Conclusion: Inflammation-mediated STAT3 activation attenuates hepatocellular injury induced by CCl4 in myeloid-specific STAT3 knockout mice, suggesting that inflammation associated with a predominance of hepatoprotective cytokines that activate hepatic STAT3 may reduce rather than accelerate hepatocellular damage in patients with chronic liver diseases. Hepatology 2010 [source]

    Novel indoloquinoline derivative, IQDMA, inhibits STAT5 signaling associated with apoptosis in K562 cells

    JOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 6 2008
    Sheng-Huei Yang
    Abstract N,-(11H-indolo[3,2-c]quinolin-6-yl)- N,N -dimethylethane-1,2-diamine (IQDMA), an indoloquinoline derivative, synthesized in our laboratory, has been demonstrated to be an effective antitumor agent in human leukemia cells. In the present study, treatment with IQDMA inhibited phosphorylation of epidermal growth factor receptor (EGFR), Src, Bcr-Abl, and Janus-activated kinase (JAK2) in a time-dependent manner. IQDMA also degraded JAK2 protein. Moreover, signal transducer and activator of transcription 5 (STAT5) signaling were also blocked by IQDMA. However, IQDMA did not inhibit other oncogenic and tumor survival pathways such as those mediated by Akt and extracellular signal-regulated kinase 1/2. Furthermore, IQDMA upregulated the expression of p21 and p27 and downregulated the expression of cyclin D1, myeloid cell leukemia-1(Mcl-1), Bcl-XL, and vascular endothelial growth factor (VEGF). Taken together, these results indicate that IQDMA causes significant induction of apoptosis in K562 cells via downregulation of EGFR, Src, Bcr-Abl, JAK2, and STAT5 signaling and modulation of p21, p27, cyclin D1, Mcl-1, Bcl-XL, and VEGF proteins. Thus, IQDMA appears to be a potential therapeutic agent for treating leukemia K562 cells. © 2008 Wiley Periodicals, Inc. J Biochem Mol Toxicol 22:396,404, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20254 [source]

    New molecular markers of early and progressive CJD brain infection

    JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 4 2004
    Zhi Yun Lu
    Abstract Transmissible spongiform encephalopathies (TSEs), including human Creutzfeldt,Jakob disease (CJD), are caused by a related group of infectious agents that can be transmitted to many mammalian species. Because the infectious component of TSE agents has not been identified, we examined myeloid cell linked inflammatory pathways to find if they were activated early in CJD infection. We here identify a specific set of transcripts in CJD infected mouse brains that define early and later stages of progressive disease. Serum amyloid A3 and L-selectin mRNAs were elevated as early as 20 days after intracerebral inoculation. Transcripts of myeloid cell recruitment factors such as MIP-1,, MIP-1,, and MCP1, as well as IL1, and TNF, were upregulated >10 fold between 30 and 40 days, well before prion protein (PrP) abnormalities that begin only after 80 days. At later stages of symptomatic neurodegenerative disease (100,110 days), a selected set of transcripts rose by as much as 100 fold. In contrast, normal brain inoculated controls showed no similar sequential changes. In sum, rapid and simple PCR tests defined progressive stages of CJD brain infection. These markers may also facilitate early diagnosis of CJD in accessible peripheral tissues such as spleen and blood. Because some TSE strains can differentially target particular cell types such as microglia, several of these molecular changes may also distinguish specific agent strains. The many host responses to the CJD agent challenge the assumption that the immune system does not recognize TSE infections because these agents are composed only of the host's own PrP. © 2004 Wiley-Liss, Inc. [source]

    A RUNX/AML-binding motif residing in a novel 13-bp DNA palindrome may determine the expression of the proximal promoter of the human uPA gene

    JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 9 2005
    E. KOPF
    Summary., Urokinase-type plasminogen activator (uPA) is a multifunctional extracellular serine protease implicated in different events including fibrinolysis, tissue remodeling, and hematopoiesis. The human uPA gene contains a major promoter region at around 2000 bp upstream from the transcription start site (+1), and a second regulatory region spanning nucleotides ,90/+32 within the proximal promoter. Here, an inspection of this region revealed a novel 13-bp palindrome residing at position +8/+20. Interestingly, the palindrome contains the DNA consensus-binding hexamer for the RUNX/AML family of transcription factors that play a role in hematopoiesis, leukemia, and several developmental processes. Measuring the expression for promoter,reporter constructs after transfection revealed that deletion of the palindrome abrogated most of the proximal promoter activity in 293A cell. Additionally, electrophoretic mobility shift assays have shown that the palindrome could bind the RUNX1 component in nuclear extracts of myeloid cell lines exclusively through its RUNX motif. The palindrome was found in five additional human genes, two of which (MYH11 and MLLT1) have been linked to chromosomal rearrangements leading to leukemia. The data presented here have implicated, for the first time, RUNX/AML in the regulation of the uPA gene. The significance of the novel palindrome regarding gene regulation through the RUNX motif deserves further investigation. [source]

    Technical aspects and clinical applications of measuring BCR-ABL1 transcripts number in chronic myeloid leukemia,

    AMERICAN JOURNAL OF HEMATOLOGY, Issue 8 2009
    Letizia Foroni
    Chronic myeloid leukemia (CML) is a myeloproliferative disorder characterized by a triphasic clinical course, the morphologic expansion of a terminally differentiated myeloid cell and the presence of the BCR-ABL1 fusion gene, the hallmark of CML. The fusion gene is usually, but not always, associated with a Philadelphia chromosome, the result of a reciprocal exchange of genetic material between chromosome 22 and chromosome 9, which leads to the production of the activated BCR-ABL1 gene and oncoprotein. The breakpoint in the BCR gene occurs commonly downstream of exons e13 or e14 (M-BCR) and less frequently downstream of exons e1 and e2 (m- BCR). Less than 1% of cases carry a breakpoint downstream of exon 6 or 8 ("variant fusion genes") or exon 19 (,- BCR). Breakpoints in the ABL1 gene cluster upstream of exon a2 (or of exon a3 in less than 5% of patients with CML). Conventional cytogenetic, fluorescence in situ hybridization, and molecular testing for the BCR-ABL1 fusion gene are key investigations for the diagnosis and monitoring of CML. Treatment using tyrosine kinase inhibitors has revolutionized the management of CML with hematologic and cytogenetic response within 12,18 months observed in >85% of patients. Nevertheless, between 15 and 20% of patients may evolve to blastic phase. Measurement of low level or "minimal" residual disease using molecular tests is becoming the gold-standard approach to measure response to therapy due to its higher sensitivity compared to other routine techniques. The technical aspects and clinical applications of molecular monitoring will be the main focus of this article. Am. J. Hematol., 2009. © 2009 Wiley-Liss, Inc. [source]

    Enhanced Th1 and Th17 responses and arthritis severity in mice with a deficiency of myeloid cell,specific interleukin-1 receptor antagonist

    ARTHRITIS & RHEUMATISM, Issue 2 2010
    Céline Lamacchia
    Objective The balance between interleukin-1 (IL-1) and its specific inhibitor, the IL-1 receptor antagonist (IL-1Ra), plays a major role in the development of arthritis. The purpose of this study was to investigate the role of IL-1Ra produced specifically by myeloid cells in the control of collagen-induced arthritis (CIA) by using myeloid cell,specific IL-1Ra,deficient mice (IL-1Ra,M). Methods IL-1Ra,M mice were generated by using the loxP/Cre recombinase system. CIA was induced in IL-1Ra,M mice and littermate control mice by a single immunization with bovine type II collagen (CII) in Freund's complete adjuvant. Arthritis severity was assessed by clinical and histologic scoring. Draining lymph node (DLN) cell responses were examined ex vivo, and ankle extracts were used in the quantification of cytokines and chemokines. Results Clinical and histopathologic evaluations revealed an early disease onset and a severe form of CIA in IL-1Ra,M mice. This was characterized by increased production of interferon-, (IFN,) and IL-17 by CII-stimulated DLN cells. We also observed that the CII-specific CD4+ T cell response shifted in vivo, from a dominant Th1 response early in the course of the arthritis to the presence of both Th1 and Th17 cytokines later in the disease course. Interestingly, IL-1Ra levels were higher in the arthritic joints of IL-1Ra,M mice as compared with the controls, indicating that nonmyeloid cells strongly contribute to the local production of IL-1Ra. However, this enhanced IL-1Ra production was not sufficient to limit joint inflammation and tissue damage. Conclusion Our results suggest that myeloid cell,derived IL-1Ra plays a critical role in the control of the development and the severity of CIA by modulating Th1 and Th17 responses in lymphoid organs. [source]

    Activation of sphingosine kinase mediates suppressive effect of interleukin-6 on human multiple myeloma cell apoptosis

    BRITISH JOURNAL OF HAEMATOLOGY, Issue 5 2007
    Qing-Fang Li
    Summary Interleukin 6 (IL-6) influences the growth and survival of multiple myeloma (MM) cells via the activation of multiple signalling cascades. Although sphingosine kinase (SPHK) signalling is known to play important roles in the regulation of cell proliferation and apoptosis, the role of SPHK activation in IL-6 signalling and in the pathology of MM remains unclear. This study found that IL-6 activated SPHK in MM cells, which mediates the suppressive effects of IL-6 on MM cell apoptosis. Both MM cell lines and primary MM cells constitutively expressed SPHK, and treatment of MM cells with IL-6 resulted in activation of SPHK in a concentration-dependent manner. Specific inhibitors of the phosphatidylinositol-3 kinase and extracellular signal-regulated kinase/mitogen-activated protein kinase pathways blocked the IL-6-induced activation of SPHK. It was further demonstrated that IL-6-induced activation of SPHK inhibited dexamethasone-induced apoptosis of MM cells. IL-6 stimulation or retroviral-mediated overexpression of SPHK1 in MM cells resulted in increased intracellular SPHK activity and upregulation of myeloid cell leukaemia-1 (Mcl-1), leading to increased cell proliferation and survival. Conversely, inhibition of SPHK1 by small interfering RNA reduced IL-6-induced upregulation of Mcl-1 and blocked the suppressive effect of IL-6 on MM cell apoptosis. Taken together, these results delineate a key role for SPHK activation in IL-6-induced proliferation and survival of MM cells, and suggest that SPHK may be a potential new therapeutic target in MM. [source]

    Gene therapy for posterior uveitis

    ACTA OPHTHALMOLOGICA, Issue 2009
    AD DICK
    Purpose To investigate the role of gene therapy incorporating release of immunomodulatory cytokines in animal models of intraocular inflammation Methods By inoculating with either AAV or lente viruses incorporating genes for IL-1RA or IL-10 into either the anterior chamber or subretinally we onserved the ability to suppress either endotoxin induced uveitis (EIU) or experimental autoimmiune uveoretinitis (EAU). Results Anterior chamber inoculation with lente-IL-10 or IL-1RA successfully suppresses inflammation and protein exudation into the eye during the course of EIU. Subretinal injection of AAV-IL-10 suppresses EAU. The extent of local macrophage activation is also suppressed as there is marked reduction in nitrotyrosine expression within the retina. Conclusion Gene therapy with immunomodulatory cytokines offers a potential to suppress active inflammatory processes within the retina. Mechanisms will be discussed in the talk in relation to macrophage activation and restoring myeloid cell (microgolial) homeostasis within the retina. [source]

    Desloratadine partially inhibits the augmented bacterial responses in the sinuses of allergic and infected mice

    CLINICAL & EXPERIMENTAL ALLERGY, Issue 10 2004
    V. Kirtsreesakul
    Summary Background Allergic rhinitis (AR) is considered a major predisposing factor for the development of acute bacterial rhinosinusitis. How AR augments a bacterial infection is unknown. Objective Our purpose in this study was to test whether an H1 receptor antagonist, desloratadine, could reduce the augmented effect of an ongoing allergic reaction on acute bacterial rhinosinusitis. Methods Three groups of infected and ovalbumin (OVA)-sensitized mice were studied: (1) infected and allergic mice treated with desloratadine, (2) infected and allergic mice treated with placebo, and (3) infected mice. A fourth group of uninfected, non-sensitized mice served as a control for the cellular changes. BALB/c mice were sensitized by two intraperitoneal injections of OVA given 8 days apart. One day after the second injection, the mice were nasally exposed daily to 6% OVA (the groups treated with desloratadine or placebo) or phosphate-buffered saline (PBS) (the infection-only group) for 5 days. After the second OVA exposure, the mice were intranasally inoculated with Streptococcus pneumoniae. Desloratadine or placebo was given daily throughout the OVA exposure period. Nasal allergic symptoms were observed by counting of nasal rubbing and sneezing for 10 min after OVA or PBS nasal challenge. On day 5 post-infection, nasal lavage culture was done, and the inflammatory cells in the sinuses were evaluated by flow cytometry. Results Mice that were made allergic, infected, and treated with placebo showed more organisms and phagocytes than did only infect mice. They also manifested allergic nasal symptoms and eosinophil influx into the sinuses. Desloratadine treatment during allergen exposure reduced allergic symptoms and reduced sinonasal infection (P<0.05). There tended to be less myeloid cell and neutrophil influx (P=0.09 both), but not eosinophil influx (P=0.85) compared with that in the placebo-treated group. Conclusion Desloratadine treatment during nasal challenge inhibited allergic symptoms and reduced sinonasal infection, suggesting that histamine via an H1 receptor plays a role in the augmented infection in mice with an ongoing allergic reaction. [source]

    Expression of WASP and Scar1/WAVE1 actin-associated proteins is differentially modulated during differentiation of HL-60 cells

    CYTOSKELETON, Issue 4 2003
    Sophie Launay
    Abstract The Wiskott-Aldrich Syndrome (WAS) is a disease associated with mutations in the WAS gene and characterised by developmental defects in haematopoietic cells such as myeloid cells. The Wiskott-Aldrich Syndrome protein (WASP)-family includes Scar1 and WASP, which are key regulators of actin reorganization in motile cells. To understand the roles of Scar1 and WASP in myeloid cells and their cytoskeletal control in haematopoietic tissues, we have explored their expression during differentiation of the promyeloid cell line HL-60. Undifferentiated HL-60 cells expressed Scar1 and WASP, and differentiation to neutrophils, induced by retinoic acid or non-retinoid agent treatments, led to a decrease in the level of expression of Scar1, whereas WASP expression was unaffected. Differentiation to monocytes/macrophages, induced by phorbol ester treatment, resulted in a decreased expression of both proteins in the adherent mature cells. Vitamin D3 treatment or cytochalasin D in combination with PMA treatment did not affect WASP expression suggesting that adhesion and cytoskeletal integrity were both essential to regulate WASP expression. Scar1 expression was regulated by differentiation, adhesion, and cytoskeletal integrity. Recently, WASP was found to colocalize with actin in the podosomes. In contrast, we show here that Scar1 did not localize with the podosomes in mature monocytes/macrophages. These observations show for the first time that modulation of Scar1 and WASP expression is a component of the differentiation program of myeloid precursors and indicate that WASP and Scar1 have different roles in mature myeloid cells. Cell Motil. Cytoskeleton 54:274,285, 2003. © 2003 Wiley-Liss, Inc. [source]

    Dermal benzene and trichloroethylene induce aneuploidy in immature hematopoietic subpopulations in vivo

    ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 3 2001
    Cynthia R. Giver
    Abstract Accumulation of genetic damage in long-lived cell populations with proliferative capacity is implicated in tumorigenesis. Hematopoietic stem cells (hsc) maintain lifetime hematopoiesis, and recent studies demonstrate that hsc in leukemic patients are cytogenetically aberrant. We postulated that exposure to agents associated with increased leukemia risk would induce genomic changes in cells in the hsc compartment. Aneusomy involving chromosomes 2 and 11 in sorted hsc (Lin,c-kit+Sca-1+) and maturing lymphoid and myeloid cells from mice that received topical doses of benzene (bz) or trichloroethylene (TCE) was quantified using fluorescence in situ hybridization. Six days after bz or TCE exposure, aneuploid cells in the hsc compartment increase four- to eightfold in a dose- and schedule-independent manner. Aneuploid lymphoid and myeloid cells from bz- and TCE-treated mice approximate controls, except after repeated benzene exposures. Aneuploid cells are more frequent in the hsc compartment than in mature hematopoietic subpopulations. Hematotoxicity was also quantified in bz- and TCE-exposed hematopoietic subpopulations using two colony-forming assays: CFU-GM (colony-forming units/granulocyte-macrophage progenitors) and CAFC (cobblestone area,forming cells). Data indicate that bz is transiently cytotoxic (,1 week) to hsc subpopulations, and induces more persistent toxicity (>2 weeks) in maturing, committed progenitor subpopulations. TCE is not hematotoxic at the doses applied. In conclusion, we provide direct evidence for induction of aneuploidy in cells in the hsc compartment by topical exposure to bz and TCE. Disruption of genomic integrity and/or toxicity in hsc subpopulations may be one step in leukemic progression. Environ. Mol. Mutagen. 37:185,194, 2001. © 2001 Wiley-Liss, Inc. [source]

    Quantitative, phenotypic, and functional evaluation of basophils in myelodysplastic syndromes

    EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 10 2001
    W. Füreder
    Background The myelodysplastic syndromes (MDS) are a group of clonal haematological disorders characterized by cytopenia(s), reduced differentiation-capacity of myeloid cells, and impaired leukocyte function. However, little is known so far about basophil granulocytes in MDS. Design We have compared the numbers, phenotype and function of basophils in MDS patients with those in healthy subjects. A total numer of 23 patients with MDS (refractory anaemia, n = 8; refractory anaemia with ringsideroblasts, n = 7; refractory anaemia with excess of blasts/refractory anaemia with excess of blasts in transformation, n = 8) and 20 healthy donors were included. Results The numbers of blood basophils in MDS patients (34·6 ± 62·9 ,L,1) was lower compared to healthy controls (58·6 ± 64·9 ,L,1). Correspondingly, whole blood histamine levels were lower in MDS patients (MDS 34·1 ± 29·1 ng mL,1 vs. normal donors 72·0 ± 36·9 ng mL,1). Like ,normal' basophils, basophils in MDS expressed interleukin-3 receptor , (CD123), E-NPP3 (CD203c), CR1 (CD35), CR3 (CD11b), CR4 (CD11c), membrane co-factor protein (CD46), decay-accelerating factor (CD55) and membrane attack complex inhibitory factor (CD59), as well as receptors for C3a, C5a (CD88), and IgE. Recombinant human (rh) C5a and anti-IgE induced significant release of histamine from basophils in both groups of donors without significant differences between MDS and healthy controls. Conclusions The absolute numbers of basophils in MDS patients are lower than in normal donors. However, basophils in MDS do not differ from their ,normal counterparts' in terms of complement receptor expression, IgE-receptor expression, or functional responses to respective ligands. [source]

    Severe vitamin B12 deficiency resulting in pancytopenia, splenomegaly and leukoerythroblastosis

    EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 5 2008
    Thorvardur R. Halfdanarson
    Abstract Deficiency of vitamin B12 is a well known cause of megaloblastic anemia and pancytopenia. Splenomegaly and leukoerythroblastosis are much less well known manifestations of B12 deficiency. We report a B12 deficient female with severe pancytopenia including normocytic anemia who also had enlarged spleen and circulating nucleated red blood cells as well as circulating immature myeloid cells. Although these findings are reported in the earlier literature, more modern reviews of the subject often fail to mention this association. We review the literature on these unusual manifestations of B12 deficiency and remind clinicians that splenomegaly and erythroblastosis can serve as diagnostic clues in cases of severe megaloblastic anemia secondary to B12 deficiency. [source]

    The soluble transferrin receptor in dysplastic erythropoiesis in myelodysplastic syndrome

    EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 1 2007
    Georgia Metzgeroth
    Abstract Objectives:,In individuals without iron deficiency, the soluble transferrin receptor (sTfR) directly reflects the erythropoietic activity. This study investigated sTfR concentrations in ineffective, dysplastic erythropoiesis in myelodysplastic syndrome (MDS). Methods:,To exclude influences of other myeloid cells on sTfR, only patients with refractory anemia (RA), refractory anemia with ringed sideroblasts (RARS) and 5q, syndrome were included. sTfR was measured nephelometrically (normal range 0.81,1.75 mg/L). Results:,Thirty-four untreated MDS patients (RA = 14, RARS = 10, 5q, syndrome = 10) were enrolled and analysed. The mean sTfR value of all MDS patients (1.30 ± 0.8 mg/L, range 0.2,3.8) did not differ from our control group. In 5q, syndrome, the mean sTfR concentration (0.80 ± 0.5 mg/L) was significantly lower than in RA (1.32 ± 0.4 mg/L, P = 0.02) and RARS (1.75 ± 1.1 mg/L, P = 0.03). Subdividing MDS according to their amount of erythroid mass in bone marrow a significant difference of sTfR between patients with decreased (0.70 ± 0.4 mg/L), normal (1.32 ± 0.4 mg/L) and increased (2.06 ± 0.9 mg/L) erythropoiesis was observed. MDS patients with sTfR values below the reference range of 0.81 mg/L required transfusions in 90% of cases and showed higher erythropoietin levels compared to MDS patients with sTfR levels ,0.81 mg/L (P = 0.01). There was a good agreement between sTfR and the amount of polychromatic erythroblasts observed (r = 0.68, P < 0.001). Conclusion:,In conclusion, the serum concentration of sTfR reflects erythropoietic activity in MDS, but it is in particular determined by the degree of erythroid maturation and the severity of ineffective erythropoiesis. Low sTfR values in MDS are associated with a reduced, poorly differentiated erythropoiesis and requirement of blood transfusions. [source]

    Tumor expression of CD200 inhibits IL-10 production by tumor-associated myeloid cells and prevents tumor immune evasion of CTL therapy

    EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 9 2010
    Lixin Wang
    Abstract CD200 is a cell-surface glycoprotein that functions through interaction with the CD200 receptor on myeloid lineage cells to regulate myeloid cell functions. Expression of CD200 has been implicated in multiple types of human cancer; however, the impact of tumor expression of CD200 on tumor immunity remains poorly understood. To evaluate this issue, we generated CD200-positive mouse plasmacytoma J558 and mastocytoma P815 cells. We found that established CD200-positive tumors were often completely rejected by adoptively transferred CTL without tumor recurrence; in contrast, CD200-negative tumors were initially rejected by adoptively transferred CTL but the majority of tumors recurred. Tumor expression of CD200 significantly inhibited suppressive activity and IL-10 production by tumor-associated myeloid cells (TAMC), and as a result, more CTL accumulated in the tumor and exhibited a greater capacity to produce IFN-, in CD200-positive tumors than in CD200-negative tumors. Neutralization of IL-10 significantly inhibited the suppressor activity of TAMC, and IL-10-deficiency allowed TAMC to kill cancer cells and their antigenic variants, which prevented tumor recurrence during CTL therapy. Thus, tumor expression of CD200 prevents tumor recurrence via inhibiting IL-10 production by TAMC. [source]

    Myeloid-derived suppressor cells in inflammation: Uncovering cell subsets with enhanced immunosuppressive functions

    EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 10 2009
    Vincenzo Bronte
    Abstract Although originally described in tumor-bearing hosts, myeloid-derived suppressor cells (MDSC) have been detected under numerous pathological situations that cause enhanced demand of myeloid cells. Thus, MDSC might be part of a conserved response to different endogenous and exogenous stress signals, including inflammation. Two processes are fundamental for MDSC biology: differentiation from myeloid progenitors and full activation of their immune regulatory program by factors released from activated T cells or present in the microenvironment conditioned by either tumor growth or inflammation. How these two processes are controlled and linked is still an open question. In this issue of the European Journal of Immunology, a paper demonstrates that a combination of the known inflammatory molecules, IFN-, and LPS, sustains MDSC expansion and activation while suppressing differentiation of DC from bone marrow precursors. Moreover, this paper contributes to defining the cell subsets that possess immunoregulatory properties within the broad population of CD11b+Gr-1+ cells, often altogether referred to as MDSC. [source]

    Increased TLR responses in dendritic cells lacking the ITAM-containing adapters DAP12 and FcR,

    EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 1 2008
    Ching-Liang Chu Dr.
    Abstract The inhibitory effect of DAP12 on macrophages has been revealed by examining myeloid cells from DAP12-deficient mice. In this report, we demonstrate that both DAP12 and the Fc,RI,-chain (FcR,) are required for negative regulation of TLR responses in bone marrow-derived dendritic cells (DC). Loss of both DAP12 and FcR, enhanced the pro-inflammatory cytokine production and maturation of DC after TLR stimulation, resulting in a greater percentage of DC that produced IL-12 p40, TNF, and IL-6, and expressed high levels of MHC class II, CD80, and CD86. Whereas DC lacking only DAP12 showed some increased TLR responses, those lacking only FcR, had a greater enhancement of maturation and cytokine production, though to a lesser extent than DC lacking both DAP12 and FcR,. Additionally, antigen-specific T cell proliferation was enhanced by DAP12,/,FcR,,/, DC relative to wild-type DC after maturation. Similar to DAP12,/,FcR,,/, DC, Syk-deficient DC also had increased inflammatory cytokine production, maturation, and antigen presentation. These results confirm the inhibitory effect of immunoreceptor tyrosine-based activation motif (ITAM) signaling in myeloid cells and show that DC and macrophages differ in their dependence on the ITAM-containing adapters DAP12 and FcR, for negative regulation of TLR signaling. [source]

    TREM-1 expression in macrophages is regulated at transcriptional level by NF-,B and PU.1

    EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 8 2007
    Heng Zeng
    Abstract Triggering receptor expressed on myeloid cells (TREM)-1 is a recently identified immunoglobulin receptor that is expressed on neutrophils and monocytes where it amplifies the acute inflammatory response to bacteria. We examined the transcriptional regulation of TREM-1 in macrophages. Treatment of RAW cells with Escherichia coli LPS or Pseudomonas aeruginosa led to the induction of TREM-1 within 1,h with an expression lasting up to at least 24,h in vitro as detected by RT-PCR. Since the promoter of TREM-1 has multiple binding sites for NF-,B and PU.1 (one of the members of the ets family of transcription factors), we investigated the role of these transcription factors in the induction of TREM-1. Treatment of cells with NF-,B inhibitors abolished the expression of message of TREM-1 induced by LPS and P.,aeruginosa. In contrast, the expression of TREM-1 was increased after stimulation with LPS or P.,aeruginosa in cells that had gene of PU.1 silenced. Additionally, over-expression of PU.1 led to inhibition of TREM-1 induction in response to LPS and P.,aeruginosa. These data suggest that both these transcription factors are involved in the expression of TREM-1. NF-,B functions as a positive regulator whereas PU.1 is a negative regulator of the TREM-1 gene. [source]

    The zinc finger protein Gfi1 acts upstream of TNF to attenuate endotoxin-mediated inflammatory responses in the lung

    EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 2 2006
    Jianmin Jin
    Abstract Gfi1 is a 55-kD nuclear zinc finger protein that is differentially expressed in lymphoid and myeloid cells. Gfi1,/, mice show a very strong systemic response to the endotoxin LPS and die rapidly within 36,h with symptoms of septic shock. Here we report that the pathohysiological processes for this exaggerated inflammatory response take place in the lung. After LPS treatment, lungs of Gfi1,/, mice showed a rapid accumulation of mononuclear cells and a significant overproduction of inflammatory cytokines such as TNF, IL-1, and IL-6. Increased cytokine production was also observed in blood-free perfused lungs from Gfi1,/, mice exposed to either LPS or overventilation. Alveolar macrophages but not airway epithelial cells from Gfi1,/, mice were found to be responsible for the enhanced cytokine production. Strikingly, when the TNF gene was deleted, Gfi1,/, animals were completely rescued from LPS hypersensitivity and had significantly lower IL-1, and IL-6 levels. We conclude that the unrestrained endotoxin response of Gfi1,/, mice occurs mainly in the lung and that Gfi1 represents a novel factor limiting the inflammatory immune response of this organ, and propose that Gfi1 exerts its regulatory function in alveolar macrophages downstream of the LPS receptor (TLR4) and upstream of TNF. [source]

    Depletion of immature B,cells during Trypanosoma cruzi infection: involvement of myeloid cells and the cyclooxygenase pathway

    EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 6 2005
    Elina Zuniga
    Abstract The ability of a microorganism to elicit or evade B,cell responses represents a determinant factor for the final outcome of an infection. Although pathogens may subvert humoral responses at different stages of B,cell development, most studies addressing the impact of an infection on the B,cell compartment have focused on mature B,cells within peripheral lymphoid organs. Herein, we report that a protozoan infection, i.e. a Trypanosoma cruzi infection, induces a marked loss of immature B,cells in the BM, which also compromises recently emigrated B,cells in the periphery. The depletion of BM immature B,cells is associated with an increased rate of apoptosis mediated by a parasite-indirect mechanism in a Fas/FasL-independent fashion. Finally, we demonstrated that myeloid cells play an important role in B,cell depletion, since CD11b+ BM cells from infected mice secrete a product of the cyclooxygenase pathway that eliminates immature B,cells. These results highlight a previously unrecognized maneuver used by a protozoan parasite to disable B,cell generation, limiting host defense and favoring its chronic establishment. [source]

    The CD200 and CD200 receptor cell surface proteins interact through their N-terminal immunoglobulin-like domains

    EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 6 2004
    Deborah Hatherley
    Abstract CD200 (OX2) is a broadly distributed cell surface glycoprotein that interacts with a receptor on myeloid cells (CD200R) involved in regulation of macrophage function. Both CD200 and CD200R contain two Ig superfamily domains like many other leukocyte membrane proteins. Site-directed mutagenesis of CD200R showed that, like CD200, it interacted through its N-terminal domain. This indicated that the cell-cell interaction spans four Ig superfamily domains and this distance is similar to many interactions found between T,cells and antigen-presenting cells. This suggests that this topology is also important in interactions of CD200 on a variety of cells with CD200R on myeloid cells, and comparable contact sites may be important mediating regulation in other cell-cell interactions. The mutagenesis showed that the binding involved the predicted GFCC, face of its N-terminal domain, like that of CD200, suggesting that the interaction evolved from a homotypic interaction. [source]

    In vitro differentiation of lineage-negative bone marrow cells into microglia-like cells

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2010
    Daisuke Noto
    Abstract Microglia are believed to be the only resident immune cells in the CNS, originating from hematopoietic-derived myeloid cells and invading the CNS during development. However, the detailed mechanisms of differentiation and transformation of microglial cells are not fully understood. Here, we demonstrate that murine microglial cells show two morphological forms in vitro, namely, small round cells expressing CD11b, Iba1, triggering receptor expressing on myeloid cells-2 (TREM2), and weakly expressing major histocompatibility complex class II and large flat cells expressing only CD11b and Iba1. Moreover, lineage-negative bone marrow (LN) cells cultured with primary mixed glial culture cells could differentiate into only the small round microglia-like cells, despite the absence of CCR2 and Gr-1 expression. Addition of macrophage colony stimulating factor (M-CSF) to LN cell culture allowed the proliferation and expression of TREM2 in LN cells, and the addition of neutralizing anti-M-CSF antibodies suppressed the proliferation of LN cells despite the expression of TREM2. When LN cells were cultured with M-CSF, the number of small round cells in the culture was considerably low, indicating that the small round morphology of the immature cells is not maintained in the presence of only M-CSF. On the other hand, when LN cells were grown in the presence of astrocytes, the small round cells were maintained at a concentration of approximately 30% of the total population. Therefore, cell,cell contact with glial cells, especially astrocytes, may be necessary to maintain the small round shape of the immature cells expressing TREM2. [source]

    Distribution and signaling of TREM2/DAP12, the receptor system mutated in human polycystic lipomembraneous osteodysplasia with sclerosing leukoencephalopathy dementia

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2004
    Giuseppina Sessa
    Abstract Together with its adaptor protein, the adaptor protein of 12 kDa also known as KARAP and TYROBP (DAP12), triggering r (TREM2) is a stimulatory membrane receptor of the immunoglobulin/lectin-like superfamily, well known in myeloid cells. In humans, however, loss-of-function mutations of TREM2/DAP12 leave myeloid cells unaffected but induce an autosomal recessive disease characterized, together with bone cysts, by a spectrum of pathological lesions in the cortex, thalamus and basal ganglia with clinical symptoms of progressive dementia (polycystic lipomembraneous osteodysplasia with sclerosing leukoencephalopathy). Nothing was known about the role of TREM2/DAP12 in brain cell biology and physiology. By confocal immunocytochemistry we demonstrate that, in both human and mouse cerebral cortex, TREM2/DAP12, strongly expressed by microglia, is also present in a fraction of neurons but not in astrocytes and oligodendrocytes. In contrast, in the hippocampal cortex TREM2-expressing neurons are rare. Both in neurons and microglia the receptor appears to be located mostly intracellularly in a discrete compartment(s) partially coinciding with (or adjacent to) the Golgi complex/trans-Golgi network. Four nerve cell lines were identified as expressing the intracellular receptor system. In living human microglia CHME-5 and glioblastoma T98G cells, activation of TREM2 by its specific antibody induced [Ca2+]i responses, documenting its surface expression and functioning. Surface expression of TREM2, low in resting CHME-5 and T98G cells, increases significantly and transiently (60 min) when cells are stimulated by ionomycin, as revealed by both surface biotinylation and surface immunolabeling. Our results provide the first information about the expression, distribution (mostly intracellular) and functioning of TREM2/DAP12 system in nerve cells, a necessary step in the understanding of the cellular mechanisms affected in polycystic lipomembraneous osteodysplasia with sclerosing leukoencephalopathy. [source]

    Differential expression of mast cell characteristics in human myeloid cell lines

    EXPERIMENTAL DERMATOLOGY, Issue 9 2004
    Pia Welker
    Abstract:, In order to better understand the mechanisms governing display of mast cell characteristics in human myeloid cells, we have studied the mast cell phenotype in human promyelocytic (HL-60) and myelocytic (U-937, TPH-1) vs. basophilic (KU-812) and mast cell (HMC-1) lines, in part also in skin mast cells and blood monocytes, at mRNA and protein level before and after stimulation with mast cell growth factors. In unstimulated cells, mRNA for the stem cell factor (SCF) receptor c-kit and the gamma chain of the high-affinity IgE receptor (Fc,RI) was noted in all cells studied. Like mast and basophilic cells, THP-1 cells expressed the Fc,RI, and , chains and weakly histidine decarboxylase (HDC), but they lacked mRNA for mast cell-specific proteases [tryptase, chymase, carboxypeptidase A (CPA)]. In contrast, HL-60 and U-937 cells lacked Fc,RI,, but expressed tryptase and chymase, HL-60 cells also CPA. KU-812 cells failed to express the basophil-specific marker 2D7. After a 10-day culture with SCF or fibroblast supernatants, baseline mRNA expression of most mast cell characteristics was upregulated, whereas c-kit mRNA expression decreased in all but THP-1 cells. Differential mRNA expression of Fc,RI vs. protease (tryptase) was confirmed at protein level by immunocytochemistry and enzymatic activity. KU-812 cells are thus closest to skin mast cells in that they express all molecules studied, except for chymase, followed by THP-1 cells that lack all mast cell proteases. In contrast, HL-60 and U-937 cells fail to express the Fc,RI, and , chains but express most mast cell proteases. The selective and differential expression of mast cell characteristics in human myeloid cell lines suggests that induction of the mast cell phenotype is regulated by several independent genes and that mast cells and basophils branch off at early and distinct points of myeloid development. [source]

    Rat choroid plexuses contain myeloid progenitors capable of differentiation toward macrophage or dendritic cell phenotypes

    GLIA, Issue 3 2006
    Serge Nataf
    Abstract The interface between the blood and the cerebrospinal fluid (CSF) is formed by the choroid plexuses (CPs), which are specialized structures located within the brain ventricles. They are composed of a vascularized stroma surrounded by a tight epithelium that controls molecular and cellular traffic between the blood and the CSF. Cells expressing myeloid markers are present within the choroidal stroma. However, the exact identity, maturation state, and functions of these CP-associated myeloid cells are not fully clarified. We show here that this cell population contains immature myeloid progenitors displaying a high proliferative potential. Thus, in neonate rats and, to a lesser extent, in adult rats, cultured CP stroma cells form large colonies of macrophages, in response to M-CSF or GM-CSF, while, under the same conditions, peripheral blood monocytes do not. In addition, under GM-CSF treatment, free-floating colonies of CD11c+ monocytic cells are generated which, when restimulated with GM-CSF and IL-4, differentiate into OX62+/MHC class II+ dendritic cells. Interestingly, in CP stroma cultures, myeloid cells are found in close association with fibroblastic-like cells expressing the neural stem-cell marker nestin. Similarly, in the developing brain, macrophages and nestin+ fibroblastic cells accumulate in vivo within the choroidal stroma. Taken together, these results suggest that the CP stroma represents a niche for myeloid progenitors and may serve as a reservoir for brain macrophages. © 2006 Wiley-Liss, Inc. [source]

    Interplay of hepatic and myeloid signal transducer and activator of transcription 3 in facilitating liver regeneration via tempering innate immunity,

    HEPATOLOGY, Issue 4 2010
    Hua Wang
    Liver regeneration triggered by two-thirds partial hepatectomy is accompanied by elevated hepatic levels of endotoxin, which contributes to the regenerative process, but liver inflammation and apoptosis remain paradoxically limited. Here, we show that signal transducer and activator of transcription 3 (STAT3), an important anti-inflammatory signal, is activated in myeloid cells after partial hepatectomy and its conditional deletion results in an enhanced inflammatory response. Surprisingly, this is accompanied by an improved rather than impaired regenerative response with increased hepatic STAT3 activation, which may contribute to the enhanced liver regeneration. Indeed, conditional deletion of STAT3 in both hepatocytes and myeloid cells results in elevated activation of STAT1 and apoptosis of hepatocytes, and a dramatic reduction in survival after partial hepatectomy, whereas additional global deletion of STAT1 protects against these effects. Conclusion: An interplay of myeloid and hepatic STAT3 signaling is essential to prevent liver failure during liver regeneration through tempering a strong innate inflammatory response mediated by STAT1 signaling. (HEPATOLOGY 2010.) [source]

    Multiple roles of Lyn kinase in myeloid cell signaling and function

    IMMUNOLOGICAL REVIEWS, Issue 1 2009
    Patrizia Scapini
    Summary:, Lyn is an Src family kinase present in B lymphocytes and myeloid cells. In these cell types, Lyn establishes signaling thresholds by acting as both a positive and a negative modulator of a variety of signaling responses and effector functions. Lyn deficiency in mice results in the development of myeloproliferation and autoimmunity. The latter has been attributed to the hyper-reactivity of Lyn-deficient B cells due to the unique role of Lyn in downmodulating B-cell receptor activation, mainly through phosphorylation of inhibitory molecules and receptors. Myeloproliferation results, on the other hand, from the enhanced sensitivity of Lyn-deficient progenitors to a number of colony-stimulating factors (CSFs). The hyper-sensitivity to myeloid growth factors may also be secondary to poor inhibitory receptor phosphorylation, leading to impaired recruitment/activation of tyrosine phosphatases and reduced downmodulation of CSF signaling responses. Despite these observations, the overall role of Lyn in the modulation of myeloid cell effector functions is much less well understood, as often both positive and negative roles of this kinase have been reported. In this review, we discuss the current knowledge of the duplicitous nature of Lyn in the modulation of myeloid cell signaling and function. [source]

    Changes in chromatin structure and methylation of the human interleukin-1, gene during monopoiesis

    IMMUNOLOGY, Issue 3 2010
    Inga Wessels
    Summary Interleukin-1, (IL-1,) induces the expression of a variety of proteins responsible for acute inflammation and chronic inflammatory diseases. However, the molecular regulation of IL-1, expression in myeloid differentiation has not been elucidated. In this study the chromatin structure of the IL-1, promoter and the impact of methylation on IL-1, expression in monocytic development were examined. The results revealed that the IL-1, promoter was inaccessible in undifferentiated promyeloid HL-60 cells but highly accessible in differentiated monocytic cells which additionally acquired the ability to produce IL-1,. Accessibilities of differentiated cells were comparable to those of primary monocytes. Lipopolysaccharide (LPS) stimulation did not affect promoter accessibility in promyeloid and monocytic HL-60 cells, demonstrating that the chromatin remodelling of the IL-1, promoter depends on differentiation and not on the transcriptional status of the cell. Demethylation via 5-aza-2,-deoxycytodine led to the induction of IL-1, expression in undifferentiated and differentiated cells, which could be increased after LPS stimulation. Our data indicate that the IL-1, promoter is reorganized into an open poised conformation during monopoiesis being a privilege of mature monocytes but not of the entire myeloid lineage. As a second mechanism, IL-1, expression is regulated by methylation acting independently of the developmental stage of myeloid cells. [source]