Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.1.7 (acetylcholinesterase)
28,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To determine if erythropoietin affects megakaryocytopoiesis, we measured acetylcholinesterase (AchE) activity, a marker of the murine megakaryocytic lineage, after the addition of human recombinant erythropoietin to serumless murine bone marrow cultures. Erythropoietin increased AchE activity substantially. Moreover, when the hormone was added to serumless cultures of 426 isolated single megakaryocytes derived from megakaryocytic colonies, erythropoietin induced a significant increase in the diameters of these cells. From a Bayesian analysis of the likelihood that some megakaryocytes increased in DNA content during the culture period, we estimate that 61% of the cells increased in ploidy. These data indicate that the action of erythropoietin is not restricted to the erythroid lineage.
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PMID:Human recombinant erythropoietin promotes differentiation of murine megakaryocytes in vitro. 379 27

When murine (C57BL/6) bone marrow cells are cultivated with WEHI-3 conditioned media, a source of megakaryocyte-colony-stimulating activity (Mk-CSA), and phorbol myristate acetate (PMA), a previously undetected population of megakaryocyte (Mk) progenitor cells is observed. These new Mk colonies are reminiscent of erythroid bursts, in that they contain large numbers (40-500) of Mk and multiple foci (2-7) of development. These burst-forming units, Mk (BFU-Mk), are defined as having greater than or equal to 42 cells/colony and, at least, three foci of Mk development (colonies grown in soft agar cultures, all studies done at limiting dilutions; colonies detected by acetylcholinesterase [ACh-E] staining). CFU-Mk and BFU-Mk require two activities for optimal growth: Mk-CSA and PMA. However, the BFU-Mk require a tenfold greater concentration of PMA for optimal development (10(-6) vs. 10(-7) M). BFU-Mk detection is linear (over a range of 25-100 X 10(3) cells/ml), with the regression line passing through the origin. Bone marrow frequencies of these two progenitor cells are CFU-Mk, 36.7 +/- 2.5, and BFU-Mk, 7.3 +/- 0.7 per 10(5) total nucleated cells (mean +/- SEM; n = 28). The BFU-Mk have a restricted velocity sedimentation range (3.3-4.5 mmh-1 vs. 3.3-6.8 mmh-1 for CFU-Mk). Modal buoyant densities are 1.068 +/- 0.0002 and 1.070 +/- 0.002 for BFU-Mk and CFU-Mk, respectively. Thus, these cells are found among the smallest and less dense of the Mk progenitors, and are not clumps or clusters of CFU-Mk. Kinetic analysis indicates that CFU-Mk require 5-7 d for optimal growth, whereas BFU-Mk require 10-12 d. Examination of the proliferative potential (cells per colony) shows 19.3 +/- 1.5 cells per colony (n = 246 colonies) for day 10 CFU-Mk, vs. 118 +/- 6.0 for day 10 BFU-Mk (n = 163). Analysis of the cellularity/subcolony within each burst indicates 37.0 +/- 2.1 (n = 146) Mk/colony and 3.9 +/- 0.1 subcolonies/burst (n = 100). Finally, greater than 90% of the BFU-Mk contain only ACh-E positive cells, indicating that these are not mixed colonies. These results indicate that the BFU-Mk, compared with the CFU-Mk, require an increased amount of stimulation in order to differentiate, show delayed in vitro development, and have a higher proliferative potential. These data are consistent with the hypothesis that these cells are early progenitor cells in the Mk lineage that antedate the CFU-Mk.
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PMID:Phorbol diesters stimulate the development of an early murine progenitor cell. The burst-forming unit-megakaryocyte. 387 29

The enzyme activities of cultured early erythroid progenitor cells (burst-forming unit erythroid, BFU-E) were measured and were compared with the activities of mature erythrocytes. The enzyme activity of acetylcholinesterase was not detectable in the erythroblasts. The ratios of phosphofructokinase and glutathione peroxidase were low due to low enzyme activities in both the erythroblasts and erythrocytes. The ratios of triose phosphate isomerase, phosphoglycerate kinase, and adenylate kinase were low due to high enzyme activities in both the erythroblasts and erythrocytes. The ratios of hexokinase, glucose phosphate isomerase, monophosphoglyceromutase, pyruvate kinase, and adenosine deaminase were high due to high enzyme activities in the erythroblasts. The isozyme of erythroblast hexokinase was of the prototype isozyme I, while pyruvate kinase was predominantly of the prototype M2, with two hybrid isozymes to the anodal side by electrophoresis. These facts suggest that there is a greatly different metabolic pattern during the maturation of the erythroid cells.
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PMID:Enzyme activities of cultured erythroblasts. 403 55

We have grown erythroid cell colonies from two patients with paroxysmal nocturnal hemoglobinuria (PNH). At 11 to 13 days, individual bursts were picked and incubated for 24 hours with 3H-leucine in order to label total cell protein (mainly hemoglobin). After appropriate washing, each burst was subjected to a miniaturized acidified serum test, and lysis was measured by the release of radioactivity. In bursts from normal controls, lysis was 19% +/- 13% SD. By contrast, of 58 bursts from PNH patients, 14 had lysis similar to that of controls (mean 15.4% +/- 10.6%), while 44 had lysis ranging from 42.2% to 85.8% (mean 70.3% +/- 10.4%). Colonies sensitive to acidified serum were acetylcholinesterase (AchE) negative, whereas normal colonies were AchE-positive. Thus, based on two independent criteria, a dual population of erythroid burst-forming units (BFU-E) can be demonstrated in PNH. These data confirm directly the somatic mutation model of the pathogenesis of PNH, and by these methods the relative sizes of the normal and the PNH cell populations can be measured at the level of the erythroid cell precursors.
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PMID:Two populations of erythroid cell progenitors in paroxysmal nocturnal hemoglobinuria. 647 58

Normal megakaryocytes take up and store serotonin (5-hydroxytryptamine) (5-HT). Murine megakaryocyte colonies were grown in plasma clot cultures, labeled autoradiographically with 3H-5-HT-creatinine sulfate, and stained for acetylcholinesterase. Silver granules representing serotonin uptake were present over almost all acetylcholinesterase-positive cells, including both mature megakaryocytes and smaller mononuclear cells. There was no evidence of serotonin accumulation in non-acetylcholinesterase staining granulocytic, monocytic, or erythroid cells. The results of this study provide: (a) a new label to identify murine megakaryocytes and smaller mononuclear megakaryocyte precursors (progeny of CFU-M) in plasma clot cultures, (b) further evidence that immature acetylcholinesterase-positive megakaryocyte precursor cells possess the ability to take up and store serotonin, and (c) evidence that this function of megakaryocytes and megakaryocyte precursors is preserved in the artificial environment of plasma clot cultures.
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PMID:Serotonin uptake by progeny of murine megakaryocyte precursors (CFU-M) in vitro. 648 79

Two sublines of the human leukemia cell line K562 including the original cell line and three clones have been investigated for their erythroid features. All of them produce embryonic and fetal hemoglobins, glycophorin A, spectrin and true acetylcholinesterase, but to a varying extent among the cell lines. The Hb and glycophorin contents were correlated in the different K562 cell lines, whereas acetylcholinesterase was independently expressed from these two other erythroid markers. Hb accumulation is enhanced by exposure of the cells to 100 microM hemin without a significant modification of the expression of the other erythroid markers. Butyrate greatly increased the activity of acetylcholinesterase, slightly enhanced the production of hemoglobin, but did not modify the expression of glycophorin and spectrin. 12-O-tetradecanoyl-phorbol-13-acetate (TPA) induced an almost complete disappearance of glycophorin, reduced the synthesis of Hb by K562 cells and also abolished the action of hemin on Hb accumulation. Therefore, all the different K562 cell lines exhibit clear erythroid features including acetylcholinesterase. Butyrate or hemin did not induce terminal differentiation of K562 cells, whereas TPA significantly diminished the erythroid phenotype.
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PMID:Erythroid properties of K562 cells. Effect of hemin, butyrate and TPA induction. 657 18

Differentiation-dependent expression of enzyme loci was evaluated in two human leukemic cell lines, the pluripotent leukemia cell line K-562 and the promyelocytic-like cell line HL-60. Acetylcholinesterase, a marker of erythroid differentiation, was present in K-562 cells and absent in HL-60 cells. This difference between the two lines was apparently unrelated to dosage effect; other enzymes carried on trisomic chromosomes in K-562 cells did not show dosage effect. Acetylcholinesterase activity was higher in subclone K-562 (S), which shows higher expression of hemoglobin. Electrophoretic mobility of acetylcholinesterase from K-562 (S) was of fetal type.
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PMID:Expression of erythroid acetylcholinesterase in the K-562 leukemia cell line. 657 51

Acetylcholinesterase, an erythroid marker constitutively expressed in K-562 cells, can be further induced by sodium butyrate. The highest level of acetylcholinesterase induction is reached in approximately equal to 3 days, in parallel with increased hemoglobin expression. Acetylcholinesterase induction is reversible, and repeated addition of butyrate is necessary to maintain a high level of the enzyme. Actinomycin D inhibits the induction.
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PMID:Regulation of acetylcholinesterase expression in the K-562 cell line. 658 44

Growth in the presence of retinoids was found to induce erythroid differentiation in Friend murine erythroleukemia (MEL) cells in culture. The program of differentiated functions expressed by retinoid-treated cells was quite similar to that promoted by other inducers of MEL cell differentiation. For example, 70% or more of induced cells synthesized hemoglobin which accumulated to a level of 8 micrograms-10 micrograms per 10(6) cells. The level of acetylcholinesterase activity increased two to five-fold in induced cells, and induction by retinoids, like induction by dimethylsulfoxide (DMSO), promoted the appearance of cell surface lumps or 'blebs'. All-trans retinaldehyde, which promoted maximum hemoglobin and acetylcholinesterase synthesis at a concentration of 5 X 10(-7) M, was found to be a more potent inducer than all-trans retinoic acid or retinol, which both showed maximum induction at 1 X 10(-5) M. Like differentiation promoted by DMSO, retinoid-induced differentiation was inhibited by 10(-7) M dexamethasone.
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PMID:Friend erythroleukemia cell differentiation: induction by retinoids. 666 87

This study is the first report on the utilization of specific cell function to identify splenic megakaryocytic colonies. Stem cell differentiation into megakaryocytes was studied by injecting each irradiated murine syngeneic recipient with 1 x 10(6) spleen cells. Morphological identification of erythroid, granulocytic, megakaryocytic, and mixed and undifferentiated colonies was done by staining consecutive cryostat sections with hemotoxylin and eosin, benzidine, myeloperoxidase, and acetylcholinesterase. The variation in the distribution of hemopoietic colonies within the spleen was reflected in the different ratio values derived for erythroid, granulocytic, and megakaryocytic colonies at varying depth within the spleen. An increase by 50% of megakaryocyte colonies was seen within the splenic pulp in the midzone region, compared with the surface. This suggests a localized microenvironment conducive for megakaryocytopoiesis. The data emphasizes the importance of identifying colonies of all cell types in histological sections of the spleen and evaluating spleen sections at least at two levels, one adjacent to the surface and the other in the midzone area.
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PMID:Identification and distribution of megakaryocyte colonies in murine spleen. 667 4


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