Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tissue tolerance was induced in neonatal rats by the intravenous injection of bone marrow cells from adult allogeneic rat donors. After 6 to 8 weeks, lymphoid cells from rats in which tolerance had been induced were tested for mixed lymphocyte reactivity (MLR), 3H-uridine uptake, and the relationship of uridine incorporation to B and T lymphocytes. Lymph node (LN) and spleen (SPL) cells from the adult inoculated rats showed no reactivity in the MLR or normal lymphocyte transfer reaction (NLTRx), indicating that the animals were tolerant. After in vitro exposure to 3H-uridine, an abundance of small lymphocytes (SL) from these same tolerant rats were heavily labeled, in contrast to nontolerant controls, where relatively few SL were heavily labeled. In order to determine whether the heavily uridine-labeled cells were T cells or B cells, lymphoid cells from the LN and SPL of tolerant animals were exposed to either rabbit anti-AKR brain serum or rabbit anti-rat Ig conjugated with ferritin. The results showed that the heavily uridine-labeled SL of the tolerant rats were mainly Ig-positive cells.
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PMID:3H-uridine incorporation by small lymphocytes of tolerant rats: relationship to T and B lymphocytes. 12 99

Apoferritin particles were found in mouse peritoneal macrophages cultured in vitro. They were found as 20S particles in the "ribosomal fraction" of macrophages labeled with L-[14C]glutamic acid. Possibilities that they were breakdown products of ribosomes or of other well-known contaminants of the ribosomal fraction were excluded because they did not incorporate [5-3H]uridine. They were resistant to RNase and were relatively resistant to detergent. The antibody against horse spleen apoferritin precipitated about 70% of the particles in the 20S region, judging by measurement of radioactivity. On in vitro incubation with Fe2+ and suitable oxidizing agents the sedimentation coefficient of 80% of the 20S particles changed to about 60S, which corresponds to that of ferritin. SDS-polyacrylamide gel electrophoresis revealed the presence of subunit structures with the same molecular size as that of mouse liver apoferritin. Under the electron microscope, the particles appeared spherical with a relatively uniform diameter of about 130 A.
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PMID:Synthesis of apoferritin in mouse peritoneal macrophages. Characterization of 20 S particles. 82 42

The binding of Phaseolus vulgaris (PHA) isolectins L4 and E4 to the brush border membrane of differentiated Caco-2 cells was studied and the impact on cellular metabolism and microvilli was assessed. Computer analysis of the data based on binding experiments with peroxidase conjugated isolectins gave mean (SD) values for maximal binding of 2540 (151).10(-9) M for PHA-L4 and 2104 (140).10(-9) M for PHA-E4 per mg of brush border membrane protein. The dissociation constants for L4 and E4 binding were 4.3 (1.4).10(-6) M and 1.1 (0.8).10(-6) M, respectively. Incubation of differentiated Caco-2 cells for 30 minutes with ferritin conjugated PHA isolectins showed that, as indicated by the number of ferritin particles, PHA-E4 bound to the microvilli to a greater extent than PHA-L4. Ferritin particles were also localised intracellularly over endocytotic invaginations and vesicles. After incubation for 48 hours with PHA-L4 or PHA-E4, the relative incorporation of precursors for DNA, RNA, and (glyco)protein synthesis into the trichloroacetic acid insoluble fraction of the Caco-2 cells was determined. Both isolectins stimulated the incorporation of thymidine and glucosamine, but neither PHA-L4 nor PHA-E4 were able to influence the incorporation of uridine. With respect to fucose, methionine, and N-acetyl mannosamine, the stimulatory effect remained confined to PHA-E4. Since PHA-L4 and PHA-E4 were tested at the same concentrations, PHA-E4 is more effective than PHA-L4. The changes in the uptake of radioactive precursors were lost after heat inactivation of PHA-E4. Compared with control and PHA-L4 incubated Caco-2 cells, the microvilli of PHA-E4 incubated cells were shortened significantly (p less than 0.01).
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PMID:Binding of kidney bean (Phaseolus vulgaris) isolectins to differentiated human colon carcinoma Caco-2 cells and their effect on cellular metabolism. 186 41

Foamy alveolar macrophages (FAM) are observed in lungs injured by Bleomycin (BLM), but their relation to pulmonary fibrosis is not clearly understood. We purified FAM from BLM-instilled rat lungs by density gradient centrifugation on Percoll, and studied the effect of FAM on pulmonary fibrosis. The cells lavaged from the rat lungs 14 days after the administration of BLM (B) or saline (S), were applied on Percoll. After centrifugation, the cells layered on each interface were collected and named as SI, SII, SIII, and BI, BII, BIII in order of gravity. The BI layer included 8.5% of unfractionated cells (U). These BI cells were viable (88%), significantly larger than the others, nonspecific esterase positive cells, and included much ferritin and lysozyme, and were morphologically identified as alveolar macrophages (AM). Therefore, we called the BI cells FAM. We estimated the capacity of FAM (2.5 X 10(5] to synthesize DNA (3H-thymidine uptake) and RNA (3H-uridine uptake), and the activities of silica-stimulated FAM to cause proliferation of mouse thymocytes (IL-1 activity) and rat lung fibroblasts (FP activity), and to produce PGE2. FAM has a lower mitogenic activity but did not have been protein synthetic activity as compared with the others. Silica-stimulated FAM released less IL-1 than BII or BIII, and induced less fibroblast growth than BII, but induced as much as BIII, possibly because of the increased capacity of BIII cells to produce PGE2, which is known to inhibit fibroblast growth. In this way, FAM were considered to be "already activated" rather than "highly activated" cells, but the presence of FAM suggested that smaller or denser AM might receive bleomycin stimulation and release fibrogenic mediators (IL-1 or MDGF) into the alveolar spaces during FAM formation, and that AM might participate in the fibrogenic responses.
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PMID:[The effect of foamy alveolar macrophages presented in bleomycin-injured rat lungs in pulmonary fibrosis]. 247 35

Resting human T-lymphocytes show an elevated intracellular concentration of ferritin, whereas transferrin receptors are not detectable. Stimulation by phytohemagglutinin markedly lowers their ferritin content, while inducing the synthesis of transferrin receptors. Addition of iron salts (ferric ammonium citrate) in activated T-lymphocyte cultures causes a marked enhancement of both [3H]uridine and [3H]thymidine incorporation. Nevertheless, it also induces a concentration-dependent decrease in transferrin receptor synthesis, associated with a marked rise of ferritin production. Hemin treatment exerts the same effects. Addition of picolinic acid in phytohemagglutinin-stimulated cultures causes a decrease of [3H]thymidine incorporation, whereas transferrin expression is markedly enhanced. The action of iron salts and chelators is specific for transferrin receptors, since the expression of other membrane markers of activated human T-lymphocytes (interleukin-2 receptor, insulin receptor, and HLA-DR antigen) is not modified by treatment with iron or picolinic acid. These observations suggest that expression of transferrin receptors in activated T-lymphocytes is specifically modulated by their intracellular iron level, rather than their proliferative rate. Addition of picolinic acid to resting T-lymphocytes in the absence of mitogen induces a marked decrease of their ferritin content, but not the appearance of transferrin receptors. On the basis of these results, we suggest a three-step model: (a) in resting T-lymphocytes, the gene for transferrin receptor is apparently "closed," in that it is not expressed under both normal conditions and following iron deprivation. (b) After mitogen stimulus, T-lymphocytes are reprogrammed into cell cycle progression, which necessarily entails synthesis of transferrin receptors (c) Expression of these receptors is modulated by the intracellular iron level, rather than the rate of proliferation per se.
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PMID:Expression of transferrin receptors in phytohemagglutinin-stimulated human T-lymphocytes. Evidence for a three-step model. 300 77

Purified antibodies were prepared to UDP-D-xylose: core protein xylosyltransferase, the enzyme which initiates the formation of chondroitin sulfate chains in the course of proteoglycan biosynthesis in cartilage. The purified antibodies were conjugated to ferritin with a two-step glutaraldehyde procedure, and conjugates were then used to locate xylosyltransferase in fragments of embryonic cartilage cells. The results indicated that the enzyme is located within the cisternae of the rough endoplasmic reticulum. The distribution of the enzyme was similar to that of prolyl hydroxylase in the same cell fragments, suggesting that procollagen synthesis and initiation of chondroitin sulfate chains occur in the same regions of the rough endoplasmic reticulum.
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PMID:Location of xylosyltransferase in the cisternae of the rough endoplasmic reticulum of embryonic cartilage cells. 642 56

The cell surface of Chlamydia psittaci seems important for establishing infection since (i) UV-treated elementary bodies (EB) attach to and are ingested by L cells and (ii) heat or antibody treatment decreases attachment to L cells and promotes the fusion of chlamydiae-containing phagosomes with lysosomes in macrophages. In the studies reported here, [3H]uridine-labeled UV-treated EB also persisted in mouse resident peritoneal macrophages and L cells, suggesting that phagosome-lysosome fusion is inhibited. We therefore chose to investigate the ingestion and internal fate of isolated purified EB envelopes in both nonprofessional and professional phagocytic cells. EB envelopes are internalized by target host cells as efficiently as are whole EB. Transmission electron microscopy of macrophages whose lysosomes were marked with ferritin revealed the persistence of individual envelopes in phagosomes devoid of ferritin for the 3-h observation period. In contrast, EB envelopes heated to 56 degrees C for 15 min were consistently found in ferritin-labeled phagolysosomes as early as 30 min. As another index of persistence, isolated EB envelopes were radioisotopically labeled with a Bolton-Hunter analog, [3H]N-succinimidyl propionate, and their fate as trichloroacetic acid-precipitable material was followed. A third probe, employed to detect the persistence of non-biodegradable antigen, was indirect immunofluorescence. Fluorescein-positive antigens were brightly visible for 7 days in both macrophages and L cells when they were inoculated with untreated EB or EB maintained in penicillin. But L cells inoculated with EB envelopes or EB treated with UV or chloramphenicol, all of which prevent the conversion of infectious EB into the metabolically active reticulate bodies, displayed reduced internal fluorescence by 2 days and the appearance of fluorescent material on the cell surface. This release of EB envelope material occurred in the absence of phagolysosome fusion. The data add credence to the belief that the spontaneous breakdown or autolytic enzyme release of EB envelope components must occur preparatory to the conversion of EB to reticulate bodies.
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PMID:Chlamydia psittaci elementary body envelopes: ingestion and inhibition of phagolysosome fusion. 684 Aug 60

Mouse erythroleukemia (MEL) cells transformed by Friend virus and induced to undergo erythroid differentiation by treatment with hexamethylenebisacetamide (HMBA) increase erythroid specific 5-aminolevulinate synthase (ALAS-E) mRNA levels by 4-15-fold and decrease "housekeeping" 5-aminolevulinate synthase (ALAS-N) mRNA levels by 1.2-1.4-fold. Iron affects translation of (ALAS-E) mRNA but nothing is known about its effect at the pretranslational level of the expression of (ALAS-E) mRNA. The aim of this study was to examine the effect of iron on the synthesis of (ALAS-E) mRNA and (ALAS-N) mRNA. This effect was compared with the effect of iron on the iron on the synthesis of H-ferritin and transferrin receptor mRNAs. Incubation of uninduced or induced MEL cells with iron chelator pyridoxal isonicotinoyl hydrazone (PIH) or desferrioxamine (Desferal) and 3H-uridine decreased the level of the 3H-labeled (ALAS-E) mRNA. The treatment with either diferric transferrin or Fe-PIH increased the level of the 3H-labeled (ALAS-E) mRNA. The opposite effect was observed on the level of the 3H-labeled (ALAS-N) mRNA. These findings indicate that iron might play its role also at the pretranslational level of the expression of ALAS-E or in the stability of (ALAS-E) mRNA.
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PMID:The role of iron supply in the regulation of 5-aminolevulinate synthase mRNA levels in murine erythroleukemia cells. 884 57

We have recently screened 36 analogues of the lipophilic iron (Fe) chelator, pyridoxal isonicotinoyl hydrazone (PIH), for their antiproliferative effect (Richardson et al, Blood 86:4295, 1995). Of these compounds, 1 chelator derived from salicylaldehyde benzoyl hydrazone (206) and 4 ligands derived from 2-hydroxy-1-naphthylaldehyde benzoyl hydrazone (308, 309, 311, and 315) showed pronounced antiproliferative activity, being far more effective than desferrioxamine (DFO). The present study was designed to investigate in detail the mechanism of action of these PIH analogues in a variety of neoplastic cell lines. This investigation showed that the analogues were far more active than DFO at inhibiting cellular proliferation and 3H-thymidine, 3H-leucine, and 3H-uridine incorporation. Additional experiments showed that, in contrast to DFO, the 5 analogues were potent at preventing 59Fe uptake from transferrin (Tf) and increasing 59Fe release from cells at concentrations as low as 10 micromol/L. Examination of the distribution of 59Fe in neoplastic cells using native polyacrylamide gel electrophoresis (PAGE)/59Fe-autoradiography showed that most of the 59Fe taken up from Tf was incorporated into ferritin, although 3 other previously unrecognized components (bands A, B, and C) were also identified. Band C comigrated with 59Fe-citrate and was chelated on incubation of neuroblastoma cells with DFO, PIH, or the PIH analogues, with this compartment being the main intracellular target of these ligands. Further work showed that the effects of the chelators at inducing characteristics consistent with apoptosis or necrosis were cell line-specific, and while DFO increased the percentage of cells in the G0/G1 phases in all cell types, the effect of analogue 311 on the cell cycle was variable depending on the cell line. This study provides further evidence for the potential use of these Fe chelators as anticancer agents.
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PMID:The potential of iron chelators of the pyridoxal isonicotinoyl hydrazone class as effective antiproliferative agents II: the mechanism of action of ligands derived from salicylaldehyde benzoyl hydrazone and 2-hydroxy-1-naphthylaldehyde benzoyl hydrazone. 910 24

Reportedly, the generation of nitric oxide (NO) may lead to iron mobilization from ferritin disrupting intracellular iron homeostasis and increasing levels of reactive oxygen species. In the present study, we evaluated the role of endogenous iron in NO-induced apoptosis in PC12 cells. Apoptosis was tested by flow cytometry, fluorescence microscopy and terminal deoxynucleotidyl transferase-mediated 2'-deoxy-uridine 5'-triphosphate nick end labeling (TUNEL) technique. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. When incubated with 0.5-0.75 mM sodium nitroprusside (SNP, a chemical NO donor), PC12 cells were shown to undergo apoptosis. In addition, SNP induced a time-dependent decrease in cell viability. Since deferoxamine (0.05-0.1 mM), a powerful iron chelator, inhibited both SNP-induced apoptosis and the decrease in cell viability, we suggest that these NO effects may be dependent upon iron mobilization within the cell.
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PMID:Protective effect of deferoxamine on sodium nitroprusside-induced apoptosis in PC12 cells. 963 95


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