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Myeloid Cell Lines (myeloid + cell_line)
Selected AbstractsMicrocirculatory Dysfunction in Chronic Venous Insufficiency (CVI)MICROCIRCULATION, Issue S1 2000MICHAEL JÜNGER ABSTRACT The elevated ambulatory pressure in the peripheral venous system of chronic venous insufficiency (CVI) patients manifests itself not only in the form of disturbed macrocirculation but also and particularly in microangiopathic changes. For this reason, it is closely correlated with trophic disorders of the skin and can ultimately lead to ulceration. Using microcirculation research techniques, we are able to provide clear evidence of a typical microangiopathy in chronic venous insufficiency. Fifty CVI patients in Widmer stages I, II, and III were examined with fluorescence video microscopy, intravital video capillaroscopy, transcutaneous oxygen partial pressure measurement, TcpO2 and laser Doppler flowmetry. The effects of compression therapy with individually fitted compression stockings on capillary morphology were studied over a period of 4 weeks in 20 CVI patients in Widmer stages I and II. The capillary pressure was measured during simulated muscle contraction using a servo-null micropressure system. We periodically drew blood from the dorsalis pedis vein and a brachial vein of 11 healthy test persons and 8 patients with stage III CVI during experimental venous hypertension in order to evaluate the expression pattern of leukocyte adhesion molecules involved in inflammation: LFA-1 (CD11a), Mac-1 (CD11b), p150,95 (CD11c), CD18, VLA-4 (CD49d), and L-selectin (CD62L). In the same patients, we used immunohistochemical methods to examine clinically unaffected skin and the skin near an ulcer, focusing on the adhesion molecules ICAM-1, VCAM-1, and E-selectin. The microangiopathic changes observed with worsening clinical symptoms include a decrease in the number of capillaries, glomerulus-like changes in capillary morphology, a drop in the oxygen content (tcpO2) of the skin, increased permeability of the capillaries to low-molecular-weight substances, increased laser Doppler flux reflecting elevated subcutaneous flow, and diminished vascular reserve. These microangiopathic changes worsen in linear proportion to the clinical severity of chronic venous insufficiency. In patients with venous ulcerations, the baseline expression of LFA-1 and VLA-4 on lymphocytes, Mac-1 expression on the myeloid cell line, and L-selectin expression on all three cell lines was not significantly different from that in healthy controls. During orthostatic stress, there was a significant reduction in the expression of L-selectin in blood cells collected at foot level in the controls (p = 0.002), but not in the patients. Clinical improvement by compression therapy was accompanied by an increase in the number of nutritive capillaries, while the diameter of the capillaries and the dermal papillae was reduced. When ulcers healed in a short period (<6 weeks), we observed a concomitant increase in the number of capillaries (p < 0.05). Microangiopathy appears before trophic disorders of the skin develop. Even trophically normal skin areas may have dilated nutritive capillaries, an early sign of disturbed skin perfusion. These changes represent a plausible explanation for the development and to recurrency tendency of venous ulcers. The reduced expression of lymphocytic L-selectin in healthy controls during the orthostatic stress test may be an indication that the cells are activated by venous stasis. Clinically effective therapeutic measures improve the impaired microcirculation of the skin in the ankle area. [source] Differential expression of mast cell characteristics in human myeloid cell linesEXPERIMENTAL DERMATOLOGY, Issue 9 2004Pia 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] On the structural diversity of Shiga toxin glycosphingolipid receptors in lymphoid and myeloid cells determined by nanoelectrospray ionization tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 15 2010Petra Hoffmann Shiga toxin (Stx, synonymous to verotoxin, VT) binds with high and low affinity to the globo-series neutral glycosphingolipids (GSLs), globotriaosylceramide (Gb3Cer or Gal,4Gal,4Glc,1Cer, also known as CD77) and globotetraosylceramide (Gb4Cer or GalNAc,3Gal,4Gal,4Glc,1Cer), respectively, which represent the targets of Stxs on many different cell types. B-cell-derived Raji cells and THP-1 cells of monocytic origin are widely used for the investigation of Stx-mediated cellular response, because Stx is known to cause cell death in both cell lines. Despite their functional importance, the Stx receptors of Raji and THP-1 cells have so far not been investigated. This prompted us to explore the structures of their GSL receptors in detail by means of nanoelectrospray ionization quadrupole time-of-flight mass spectrometry (nanoESI-QTOF-MS) with collision-induced dissociation (CID) in conjunction with Stx1 as well as anti-Gb3Cer and anti-Gb4Cer antibodies. Using the combination of a thin-layer chromatography (TLC) overlay assay and MS1 and MS2 analysis we identified Gb3Cer (d18:1, C24:1/C24:0) as the prevalent Stx1-receptor accompanied by less abundant Gb3Cer (d18:1, C16:0) in the neutral GSL fraction of Raji cells. The same Gb3Cer species but with almost equal proportions of the C24:1/C24:0 and C16:0 variants were found in THP-1 cells. In addition, unusual hydroxylated Gb3Cer (d18:1, C24:1/C24:0) and Gb3Cer (d18:1, C26:1) could be identified in trace quantities in both cell lines. As the most obvious difference between Raji and THP-1 cells we observed the expression of Gb4Cer in THP-1 cells, whereas Raji cells failed to express this elongation product of Gb3Cer. Both short- and long-chain fatty acid carrying Gb4Cer (d18:1, C16:0) and Gb4Cer (d18:1, C24:1/C24:0), respectively, were the prevalent Gb4Cer variants. This first report on the differential expression of Gb3Cer and Gb4Cer and their structural diversity in lymphoid and myeloid cell lines supports the hypothesis that such heterogeneities might play a functional role in the molecular assembly of GSLs in membrane organization and cellular signaling of Stx-susceptible cells. Copyright © 2010 John Wiley & Sons, Ltd. [source] The oral iron chelator deferasirox represses signaling through the mTOR in myeloid leukemia cells by enhancing expression of REDD1CANCER SCIENCE, Issue 5 2009Junko H. Ohyashiki To evaluate the effect of deferasirox in human myeloid leukemia cells, and to identify the moleclular pathways responsible for antiproliferative effects on leukemia cells during chelation therapy, we performed gene expression profiling to focus on the pathway involved in the anticancer effect of deferasirox. The inhibitory concentration (IC50) of deferasirox was 17,50 µM in three human myeloid cell lines (K562, U937, and HL60), while those in fresh leukemia cells obtained from four patients it varied from 88 to 172 µM. Gene expression profiling using Affymerix GeneChips (U133 Plus 2.0) revealed up-regulation of cyclin-dependent kinase inhibitor 1A (CDKN1A) encoding p21CIP, genes regulating interferon (i.e. IFIT1). Pathways related to iron metabolism and hypoxia such as growth differentiation factor 15 (GDF-15) and Regulated in development and DNA damage response (REDD1) were also prominent. Based on the results obtained from gene expression profiling, we particularly focused on the REDD1/mTOR (mammalian target of rapamycin) pathway in deferasirox-treated K562 cells, and found an enhanced expression of REDD1 and its down-stream protein, tuberin (TSC2). Notably, S6 ribosomal protein as well as phosphorylated S6, which is known to be a target of mTOR, was significantly repressed in deferasirox-treated K562 cells, and REDD1 small interfering RNA restored phosphorylation of S6. Although iron chelation may affect multiple signaling pathways related to cell survival, our data support the conclusion that REDD1 functions up-stream of tuberin to down-regulate the mTOR pathway in response to deferasirox. Deferasirox might not only have benefit for iron chelation but also may be an antiproliferative agent in some myeloid leukemias, especially patients who need both iron chelation and reduction of leukemia cells. (Cancer Sci 2009; 100: 970,977) [source] | ||||||||||