BACKGROUND: Beta-lactoglobulin (BLG) is a bovine lipocalin in milk with an innate defense function. The circumstances under which BLG is associated with tolerance of or allergy to milk are not understood. OBJECTIVE: Our aims were to assess the capacity of ligand-free apoBLG versus loaded BLG (holoBLG) to protect mice against allergy by using an iron-quercetin complex as an exemplary ligand and to study the molecular mechanisms of this protection. METHODS: Binding of iron-quercetin to BLG was modeled and confirmed by spectroscopy and docking calculations. Serum IgE binding to apoBLG and holoBLG in children allergic to milk and children tolerant of milk was assessed. Mice were intranasally treated with apoBLG versus holoBLG and analyzed immunologically after systemic challenge. Aryl hydrocarbon receptor (AhR) activation was evaluated with reporter cells and Cyp1A1 expression. Treated human PBMCs and human mast cells were assessed by fluorescence-activated cell sorting and degranulation, respectively. RESULTS: Modeling predicted masking of major IgE and T-cell epitopes of BLG by ligand binding. In line with this modeling, IgE binding in children allergic to milk was reduced toward holoBLG, which also impaired degranulation of mast cells. In mice, only treatments with holoBLG prevented allergic sensitization and anaphylaxis, while sustaining regulatory T cells. BLG facilitated quercetin-dependent AhR activation and, downstream of AhR, lung Cyp1A1 expression. HoloBLG shuttled iron into monocytic cells and impaired their antigen presentation. CONCLUSION: The cargo of holoBLG is decisive in preventing allergy in vivo. BLG without cargo acted as an allergen in vivo and further primed human mast cells for degranulation in an antigen-independent fashion. Our data provide a mechanistic explanation why the same proteins can act either as tolerogens or as allergens.

• Klíčová slova
• Allergen, BLG, Bos d 5, allergy, cow's milk, iron, ligand, lipocalin, milk, quercetin, tolerance, β-lactoglobulin,
• MeSH
• alergie na mléko farmakoterapie   imunologie   MeSH
• laktoglobuliny * chemie   farmakokinetika   farmakologie   MeSH
• leukocyty mononukleární imunologie   MeSH
• lidé MeSH
• mastocyty imunologie   MeSH
• mléko chemie   MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• skot MeSH
• železo * chemie   farmakokinetika   farmakologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• laktoglobuliny * MeSH
• železo * MeSH

Yeasts Cryptococcus humicola accumulated cadmium, cobalt, and iron (~ 50, 17, and 4% of the content in the medium, respectively) from the medium containing glucose, phosphate, and 2 mmol/L of metal salts. The effects of metal absorption on the levels of orthophosphate (Pi) and inorganic polyphosphate (polyP) varied for the metals under study. The levels of Pi and polyP increased in the case of cadmium and cobalt, respectively. In the case of iron, no changes in the levels of Pi and polyP were observed. Multiple DAPI-stained polyP inclusions were observed in the cytoplasm of cadmium-containing cells. The intensity of DAPI staining of the cell wall especially increased in case of cobalt and iron accumulation.

• MeSH
• biomasa MeSH
• Cryptococcus metabolismus   MeSH
• dusík metabolismus   MeSH
• kadmium chemie   metabolismus   farmakokinetika   MeSH
• kobalt chemie   metabolismus   farmakokinetika   MeSH
• polyfosfáty chemie   metabolismus   farmakokinetika   MeSH
• sorpční detoxikace MeSH
• železo chemie   metabolismus   farmakokinetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• dusík MeSH
• kadmium MeSH
• kobalt MeSH
• polyfosfáty MeSH
• železo MeSH

Numerous cellular functions including respiration require iron. Plants and phytoplankton must also maintain the iron-rich photosynthetic electron transport chain, which most likely evolved in the iron-replete reducing environments of the Proterozoic ocean [1]. Iron bioavailability has drastically decreased in the contemporary ocean [1], most likely selecting for the evolution of efficient iron acquisition mechanisms among modern phytoplankton. Mesoscale iron fertilization experiments often result in blooms dominated by diatoms [2], indicating that diatoms have adaptations that allow survival in iron-limited waters and rapid multiplication when iron becomes available. Yet the genetic and molecular bases are unclear, as very few iron uptake genes have been functionally characterized from marine eukaryotic phytoplankton, and large portions of diatom iron starvation transcriptomes are genes encoding unknown functions [3-5]. Here we show that the marine diatom Phaeodactylum tricornutum utilizes ISIP2a to concentrate Fe(III) at the cell surface as part of a novel, copper-independent and thermodynamically controlled iron uptake system. ISIP2a is expressed in response to iron limitation several days prior to the induction of ferrireductase activity, and it facilitates significant Fe(III) uptake during the initial response to Fe limitation. ISIP2a is able to directly bind Fe(III) and increase iron uptake when heterologously expressed, whereas knockdown of ISIP2a in P. tricornutum decreases iron uptake, resulting in impaired growth and chlorosis during iron limitation. ISIP2a is expressed by diverse marine phytoplankton, indicating that it is an ecologically significant adaptation to the unique nutrient composition of marine environments.

• MeSH
• druhová specificita MeSH
• fytoplankton metabolismus   MeSH
• membránové proteiny metabolismus   MeSH
• mořská biologie MeSH
• mořská voda chemie   MeSH
• rozsivky metabolismus   MeSH
• stanovení celkové genové exprese MeSH
• terciární struktura proteinů MeSH
• železo metabolismus   farmakokinetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• membránové proteiny MeSH
• železo MeSH

BACKGROUND: Magnetic resonance imaging provides a noninvasive method to study the fate of transplanted cells in vivo. OBJECTIVE: We studied the fate of embryonic and mesenchymal stem cells labeled with iron oxide nanoparticles (Endorem) and human CD34+ cells labeled with magnetic MicroBeads (Miltenyi) in rats with a cortical or spinal cord lesion. METHODS: Cells were grafted intracerebrally, contralaterally to a cortical photochemical lesion, or injected intravenously. RESULTS: During the 1st week after transplantation, transplanted cells migrated to the lesion and were visible in the lesion on MR images as a hypointensive signal, persisting for more than 30 days. In rats with a balloon-induced spinal cord compression lesion, we observed an increase in functional recovery and hind limb sensitivity after implantation of Endorem-labeled mesenchymal stem cells or a freshly prepared mononuclear fraction of bone marrow cells or after injection of granulocyte colony-stimulating factor. Morphometric measurements in the center of the lesions showed an increase in white matter volume in cell-treated animals. Prussian blue staining confirmed a large number of Prussian blue-positive cells, and the lesions were considerably smaller than in control animals. CONCLUSIONS: These studies demonstrate that magnetic resonance imaging of grafted adult as well as embryonic stem cells labeled with iron oxide nanoparticles is a useful method for evaluating their migration and fate in CNS.

• MeSH
• cévní mozková příhoda patologie   terapie   MeSH
• dextrany MeSH
• kontrastní látky farmakokinetika   MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   MeSH
• magnetické nanočástice MeSH
• mícha cytologie   MeSH
• mozek cytologie   MeSH
• oxid železnato-železitý MeSH
• oxidy farmakokinetika   MeSH
• poranění míchy patologie   terapie   MeSH
• transplantace kmenových buněk * MeSH
• železo farmakokinetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• dextrany MeSH
• ferumoxides MeSH Prohlížeč
• kontrastní látky MeSH
• magnetické nanočástice MeSH
• oxid železnato-železitý MeSH
• oxidy MeSH
• železo MeSH

We tested the effect of iron deprivation on the uptake of iron from ferric citrate by human erythroleukemia K562 cells. The iron uptake after 24-h preincubation in defined iron-free medium was approximately 2-3x higher than after the preincubation in control transferrin-containing medium. The preincubation of K562 cells in iron-free medium together with the inhibitor of protein synthesis cycloheximide completely abrogated the stimulation of the iron uptake. The preincubation in iron-free medium resulted in a slight decrease (20%) of DMT1 mRNA level. The level of Dcytb, ferroportin and hephaestin mRNA did not exert any significant change. We also did not find any significant effect on the protein level of DMT1, Dcytb, ferroportin and hephaestin. We conclude that iron deprivation stimulates the uptake of non-transferrin iron in K562 cells and that this stimulation depends on protein synthesis. It seems that the expression of an unknown or seemingly unrelated protein(s) is involved.

• MeSH
• buňky K562 MeSH
• časové faktory MeSH
• cykloheximid farmakologie   MeSH
• lidé MeSH
• nádorové buňky kultivované MeSH
• proteiny regulující obsah železa antagonisté a inhibitory   biosyntéza   MeSH
• transferin metabolismus   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• železo metabolismus   farmakokinetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• cykloheximid MeSH
• proteiny regulující obsah železa MeSH
• transferin MeSH
• železo MeSH

Iron is an essential element involved in many life-necessary processes. Interestingly, in mammals there is no active excretion mechanism for iron. Therefore iron kinetics has to be meticulously regulated. The most important step for regulation of iron kinetics is absorption. The absorption takes place in small intestine and it is implicated that it requires several proteins. Iron is then released from enterocytes into the circulation and delivered to the cells. Iron movement inside the cell is only partially elucidated and its traffic to mitochondia is not known. Surprisingly, the regulation of various proteins related to iron kinetics and energy metabolism at the molecular level is better described. On contrary, the complex control of iron absorption cannot be fully explicated with present knowledge.

• MeSH
• absorpce MeSH
• lidé MeSH
• proteiny regulující obsah železa metabolismus   MeSH
• tenké střevo metabolismus   MeSH
• železo metabolismus   farmakokinetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• proteiny regulující obsah železa MeSH
• železo MeSH

The exact mechanisms of iron transport from endosomes to the target iron containing cellular proteins are currently unknown. To investigate this problem, we used the gradient gel electrophoresis and the sensitive detection of 59Fe by autoradiography to detect separate cellular iron compounds and their iron kinetics. Cells of human leukemic line K562 were labeled with [59Fe]transferrin for 30-600 s and cellular iron compounds in cell lysates were analyzed by native electrophoretic separation followed by 59Fe autoradiography. Starting with the first 30 s of iron uptake, iron was detectable in a large membrane bound protein complex (Band I) and in ferritin. Significant amounts of iron were also found in labile iron compound(s) with the molecular weight larger than 5000 as judged by ultrafiltration. Iron kinetics in these compartments was studied. Band I was the only compound with the kinetic properties of an intermediate. Transferrin, transferrin receptor and additional proteins of the approximate molecular weights of 130000, 66000 and 49000 were found to be present in Band I. The labile iron compounds and ferritin behaved kinetically as end products. No evidence for low molecular weight transport intermediates was found. These results suggest that intracellular iron transport is highly compartmentalized, that iron released from endosomal transferrin passes to its cellular targets in a direct contact with the endosomal membrane complex assigned as Band I. The nature of the labile iron pool and its susceptibility to iron chelation is discussed.

• MeSH
• autoradiografie MeSH
• biologické modely MeSH
• biologický transport MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• endozomy metabolismus   MeSH
• frakcionace buněk MeSH
• lidé MeSH
• nádorové buňky kultivované MeSH
• radioizotopy železa MeSH
• receptory transferinu metabolismus   MeSH
• transferin farmakokinetika   MeSH
• transportní proteiny izolace a purifikace   MeSH
• železo farmakokinetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• radioizotopy železa MeSH
• receptory transferinu MeSH
• transferin MeSH
• transportní proteiny MeSH
• železo MeSH

We studied transport of non-transferrin iron into HeLa cells adapted for growth in defined medium, containing either 5 micrograms/ml of iron-saturated transferrin (HeLa/Tf cells) or 5 microM ferric citrate (HeLa/Fe5 cells) as a source of iron. Employing 55Fe-ferric citrate, iron uptake by intact cells was compared with iron binding to isolated membranes. Uptake characteristics of both HeLa/Tf and HeLa/Fe5 cells seemed to be similar: Km = 14 microM and Vmax = 135 pmol Fe/min/10(5) cells for HeLa/Tf, Km = 22 microM and Vmax = 165 pmol Fe/min/10(5) cells for HeLa/Fe5. Increasing concentrations (0.3-1.2 microM) of 55Fe-ferric citrate, producing levels of free 55Fe which were independent of total Fe under the experimental conditions used, led to increased binding of 55Fe for both HeLa/Tf and HeLa/Fe5 cells (1.08-8.03 nmol Fe/h/10(5) cells). This corresponds with the suggestion that iron was bound in the form of ferric citrate rather than in the form of free iron. Dissociation constants of Fe binding, KD = 0.61 microM for HeLa/Tf and KD = 1.53 microM for HeLa/Fe5, were obtained from competition experiments. We conclude that specific binding sites for ferric citrate are constitutively expressed in plasma membrane and that their expression does not require the induction by the presence of ferric citrate. The uptake of non-transferrin iron is realized in at least two steps. The first step is iron binding to the specific binding sites in plasma membrane. The binding does not represent a limiting step of the uptake.

• MeSH
• biologický transport MeSH
• buněčná membrána metabolismus   MeSH
• buněčné klony MeSH
• HeLa buňky MeSH
• lidé MeSH
• transferin metabolismus   MeSH
• vazebná místa MeSH
• železo metabolismus   farmakokinetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• transferin MeSH
• železo MeSH

Haemin inhibited iron uptake from transferrin (Tf) by mouse erythroleukaemia cells (MELC) induced for differentiation by hexamethylene bisacetamide (HMBA). The rate of 59Fe internalization was decreased, but the rate and the extent of 125I-Tf endocytosis was unaffected by the addition of haemin. Haemin inhibited 59Fe incorporation into haem by a greater proportion than the overall uptake of 59Fe from Tf. The reduction of total cellular 59Fe uptake was more pronounced at 59Fe-Tf concentrations closer to saturation. Exogenous 5-aminolaevulinic acid stimulated 59Fe utilization for haem synthesis in MELC but did not revert the inhibition induced by haemin. Haem synthesis measured by 14C-glycine incorporation into haem was maintained for at least 1 h without an external transferrin iron source and was inhibited by the addition of haemin equally over the whole range of Tf concentrations studied. Desferrioxamine (DFO) stimulated cellular uptake of 59Fe by the uninduced cells and reverted the inhibition of 59Fe transport into HMBA treated cells caused by haemin. Addition of DFO within a short-term incubation had no effect on haem synthesis measured by 14C-glycine incorporation into haem. No evidence for a direct effect of haem on the transferrin cycle or iron release was found. It was concluded that the reduction of iron uptake by haemin treated MELC is secondary to the decrease in iron utilization for haem synthesis.

• MeSH
• acetamidy farmakologie   MeSH
• akutní erytroblastická leukemie metabolismus   MeSH
• buněčná diferenciace účinky léků   MeSH
• časové faktory MeSH
• glycin farmakokinetika   MeSH
• hem analogy a deriváty   biosyntéza   MeSH
• hemin farmakologie   MeSH
• kultivované buňky MeSH
• kyselina aminolevulová farmakologie   MeSH
• myši MeSH
• radioizotopy železa MeSH
• transferin farmakokinetika   MeSH
• železo farmakokinetika   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetamidy MeSH
• glycin MeSH
• hem MeSH
• hemin MeSH
• hexamethylene bisacetamide MeSH Prohlížeč
• kyselina aminolevulová MeSH
• radioizotopy železa MeSH
• transferin MeSH
• železo MeSH

Using the model of mice affected by thyroid hormones, a ferrokinetic analysis was made of the repeatedly observed paradoxical fall in the incorporation of labelled iron into the bone marrow under conditions of the overall stimulation of erythrocyte formation.

• MeSH
• buněčný cyklus účinky léků   MeSH
• erytropoéza účinky léků   MeSH
• hormony štítné žlázy farmakologie   MeSH
• kostní dřeň metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• radioizotopy železa MeSH
• sušená štítná žláza farmakologie   MeSH
• tkáňová distribuce MeSH
• železo farmakokinetika   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• hormony štítné žlázy MeSH
• radioizotopy železa MeSH
• sušená štítná žláza MeSH
• železo MeSH