Analysis of Ferritins in Lymphoblastoid Cell Lines and in the Lens of Subjects With Hereditary Hyperferritinemia-Cataract Syndrome

Blood ◽  
1998 ◽  
Vol 91 (11) ◽  
pp. 4180-4187 ◽  
Author(s):  
Sonia Levi ◽  
Domenico Girelli ◽  
Federica Perrone ◽  
Marcella Pasti ◽  
Carole Beaumont ◽  
...  
Keyword(s):  
Cell Lines ◽  
Iron Metabolism ◽  
Antioxidant Properties ◽  
Water Soluble ◽  
Lymphoblastoid Cell Lines ◽  
Cataract Formation ◽  
Iron Regulatory Proteins ◽  
Control Subjects ◽  
Cellular Iron ◽  
Chain Synthesis

Hereditary hyperferritinemia-cataract syndrome (HHCS) is an autosomal and dominant disease caused by heterogeneous mutations in the iron responsive element (IRE) of the 5′ untranslated flanking region of ferritin L-chain mRNA, which reduce the binding to the trans iron regulatory proteins and make L-chain synthesis constitutively upregulated. In the several families identified so far, the serum and tissue L-ferritin levels are fivefold to 20-fold higher than in nonaffected control subjects, iron metabolism is apparently normal, and the only relevant clinical symptom is early onset, bilateral cataract. Some pathogenetic aspects of HHCS remain obscure, with particular reference to the isoferritins produced by HHCS cells, as well as the mechanism of cataract formation. We analyzed lymphoblastoid cell lines obtained from two nonaffected control subjects and from HHCS patients carrying the substitution A40G (Paris-1), G41C (Verona-1), and the deletion of the residues 10-38 (Verona-2) in the IRE structure. Enzyme-linked immunosorbent assays specific for the H- and L-type ferritins showed that L-ferritin levels were up to 20-fold higher in HHCS than in control cells and were not affected by iron supplementation or chelation. Sequential immunoprecipitation experiments of metabolically-labeled cells with specific antibodies indicated that in HHCS cells about half of the L-chain was assembled in L-chain homopolymers, which did not incorporate iron, and the other half was assembled in isoferritins with a high proportion of L-chain. In control cells, all ferritin was assembled in functional heteropolymers with equivalent proportion of H- and L-chains. Cellular and ferritin iron uptake was slightly higher in HHCS than control cells. In addition, we analyzed the lens recovered from cataract surgery of a HHCS patient. We found it to contain about 10-fold more L-ferritin than control lens. The ferritin was fully soluble with a low iron content. It was purified and partially characterized. Our data indicate that: (1) in HHCS cells a large proportion of L-ferritin accumulates as nonfunctional L-chain 24 homopolymers; (2) the concomitant fivefold to 10-fold expansion of ferritin heteropolymers, with a shift to L-chain–rich isoferritins, does not have major effects on cellular iron metabolism; (3) L-chain accumulation occurs also in the lens, where it may induce cataract formation by altering the delicate equilibrium between other water-soluble proteins (ie, crystallins) and/or the antioxidant properties.

Analysis of Ferritins in Lymphoblastoid Cell Lines and in the Lens of Subjects With Hereditary Hyperferritinemia-Cataract Syndrome

Blood ◽  
1998 ◽  
Vol 91 (11) ◽  
pp. 4180-4187 ◽  
Author(s):  
Sonia Levi ◽  
Domenico Girelli ◽  
Federica Perrone ◽  
Marcella Pasti ◽  
Carole Beaumont ◽  
...  
Keyword(s):  
Cell Lines ◽  
Iron Metabolism ◽  
Antioxidant Properties ◽  
Water Soluble ◽  
Lymphoblastoid Cell Lines ◽  
Cataract Formation ◽  
Iron Regulatory Proteins ◽  
Control Subjects ◽  
Cellular Iron ◽  
Chain Synthesis

Abstract Hereditary hyperferritinemia-cataract syndrome (HHCS) is an autosomal and dominant disease caused by heterogeneous mutations in the iron responsive element (IRE) of the 5′ untranslated flanking region of ferritin L-chain mRNA, which reduce the binding to the trans iron regulatory proteins and make L-chain synthesis constitutively upregulated. In the several families identified so far, the serum and tissue L-ferritin levels are fivefold to 20-fold higher than in nonaffected control subjects, iron metabolism is apparently normal, and the only relevant clinical symptom is early onset, bilateral cataract. Some pathogenetic aspects of HHCS remain obscure, with particular reference to the isoferritins produced by HHCS cells, as well as the mechanism of cataract formation. We analyzed lymphoblastoid cell lines obtained from two nonaffected control subjects and from HHCS patients carrying the substitution A40G (Paris-1), G41C (Verona-1), and the deletion of the residues 10-38 (Verona-2) in the IRE structure. Enzyme-linked immunosorbent assays specific for the H- and L-type ferritins showed that L-ferritin levels were up to 20-fold higher in HHCS than in control cells and were not affected by iron supplementation or chelation. Sequential immunoprecipitation experiments of metabolically-labeled cells with specific antibodies indicated that in HHCS cells about half of the L-chain was assembled in L-chain homopolymers, which did not incorporate iron, and the other half was assembled in isoferritins with a high proportion of L-chain. In control cells, all ferritin was assembled in functional heteropolymers with equivalent proportion of H- and L-chains. Cellular and ferritin iron uptake was slightly higher in HHCS than control cells. In addition, we analyzed the lens recovered from cataract surgery of a HHCS patient. We found it to contain about 10-fold more L-ferritin than control lens. The ferritin was fully soluble with a low iron content. It was purified and partially characterized. Our data indicate that: (1) in HHCS cells a large proportion of L-ferritin accumulates as nonfunctional L-chain 24 homopolymers; (2) the concomitant fivefold to 10-fold expansion of ferritin heteropolymers, with a shift to L-chain–rich isoferritins, does not have major effects on cellular iron metabolism; (3) L-chain accumulation occurs also in the lens, where it may induce cataract formation by altering the delicate equilibrium between other water-soluble proteins (ie, crystallins) and/or the antioxidant properties.

Iron Regulatory Proteins in Systemic Iron Metabolism and Erythropoiesis

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. SCI-22-SCI-22
Author(s):  
Matthias W. Hentze
Keyword(s):  
Iron Metabolism ◽  
Iron Homeostasis ◽  
Mutant Mouse ◽  
Conflicts Of Interest ◽  
Regulatory Proteins ◽  
Iron Regulatory Proteins ◽  
Cellular Iron ◽  
Regulatory Systems ◽  
Biology I ◽  
Mouse Lines

Abstract Abstract SCI-22 Imbalances of iron homeostasis account for some of the most common human diseases. Pathologies can result from both iron deficiency or overload. The hepcidin/ferroportin and the IRE/IRP regulatory systems balance systemic and cellular iron metabolism, respectively, and understanding their points of intersection and crosstalk represents a major challenge in iron biology. I will discuss an emerging picture from studies with different mutant mouse lines according to which the “cellular” IRE/IRP system determines “set points” via its targets (including ferroportin and HIF2α). These are then subject to modulation via hepcidin in response to systemic cues. Disclosures: No relevant conflicts of interest to declare.

Iron regulatory protein-1 and -2: transcriptome-wide definition of binding mRNAs and shaping of the cellular proteome by iron regulatory proteins

Blood ◽  
2011 ◽  
Vol 118 (22) ◽  
pp. e168-e179 ◽  
Author(s):  
Mayka Sanchez ◽  
Bruno Galy ◽  
Bjoern Schwanhaeusser ◽  
Jonathon Blake ◽  
Tomi Bähr-Ivacevic ◽  
...  
Keyword(s):  
Iron Metabolism ◽  
Rna Binding ◽  
Isotope Labeling ◽  
Rna Binding Proteins ◽  
Regulatory Protein ◽  
Regulatory Proteins ◽  
Iron Regulatory Proteins ◽  
Ribonucleoprotein Complexes ◽  
Cellular Iron ◽  
Irp1 And Irp2

Abstract Iron regulatory proteins (IRPs) 1 and 2 are RNA-binding proteins that control cellular iron metabolism by binding to conserved RNA motifs called iron-responsive elements (IREs). The currently known IRP-binding mRNAs encode proteins involved in iron uptake, storage, and release as well as heme synthesis. To systematically define the IRE/IRP regulatory network on a transcriptome-wide scale, IRP1/IRE and IRP2/IRE messenger ribonucleoprotein complexes were immunoselected, and the mRNA composition was determined using microarrays. We identify 35 novel mRNAs that bind both IRP1 and IRP2, and we also report for the first time cellular mRNAs with exclusive specificity for IRP1 or IRP2. To further explore cellular iron metabolism at a system-wide level, we undertook proteomic analysis by pulsed stable isotope labeling by amino acids in cell culture in an iron-modulated mouse hepatic cell line and in bone marrow-derived macrophages from IRP1- and IRP2-deficient mice. This work investigates cellular iron metabolism in unprecedented depth and defines a wide network of mRNAs and proteins with iron-dependent regulation, IRP-dependent regulation, or both.

scholarly journals Parallel synthesis of immunoglobulins and J chain in pokeweed mitogen-stimulated normal cells and in lymphoblastoid cell lines.

1977 ◽  
Vol 145 (3) ◽  
pp. 760-765 ◽  
Author(s):  
J Mestecky ◽  
R J Winchester ◽  
T Hoffman ◽  
H G Kunkel
Keyword(s):  
T Cells ◽  
Cell Lines ◽  
Parallel Synthesis ◽  
Pokeweed Mitogen ◽  
Lymphoblastoid Cell Lines ◽  
B Cell Differentiation ◽  
Normal Cells ◽  
J Chain ◽  
Chain Synthesis ◽  
Lymphoid Cell Lines

The synthesis of intracellular J chains was found to be closely associated with that of intracellular immunoglobulin, regardless of its class, during the process of B-cell differentiation. This parallelism between the synthesis of J chain and immunoglobulin was particularly evident in their coincident appearance in serial observations of pokeweed mitogen (PWM)-stimulated lymphocytes. The intensity of J-chain staining by fluorescent reagents in the stimulated cells synthesizing IgG was similar to that found in cells synthesizing IgA or IgM. Evidence was obtained that the presence of J chain in the IgG-producing cells did not reflect antecedent synthesis of IgA or IgM. T cells stimulated by phytohemagglutinin and PWM failed to show J-chain synthesis. Observations on lymphoid cell lines showed a similar parallelism between intracellular Ig and J-chain synthesis; no relation to surface Ig was found.

­Dysregulation of the sensory and regulatory pathways controlling cellular iron metabolism in unilateral obstructive nephropathy

2021 ◽  
Author(s):  
James A Votava ◽  
Shannon Reese ◽  
Kathryn M Deck ◽  
Christopher P Nizzi ◽  
Sheila Anderson ◽  
...  
Keyword(s):  
Iron Metabolism ◽  
Kidney Failure ◽  
Rna Binding ◽  
Binding Activity ◽  
Iron Storage ◽  
Iron Regulatory Proteins ◽  
Regulatory Pathways ◽  
Genetic Ablation ◽  
Cellular Iron ◽  
The Impact

Chronic kidney disease (CKD) involves disturbances in iron metabolism including anemia caused by insufficient erythropoietin (EPO) production. However, underlying mechanisms responsible for the dysregulation of cellular iron metabolism are incompletely defined. Using the unilateral ureteral obstruction (UUO) model in Irp1+/+ and Irp1-/- mice we asked if iron regulatory proteins (IRP), the central regulators of cellular iron metabolism and also suppressors of EPO production, contribute to the etiology of anemia in kidney failure. We identified a significant reduction in IRP protein level and RNA binding activity that associated with a loss of the iron uptake protein transferrin receptor 1, increased expression of the iron storage protein subunits H- and L-ferritin, and a low but overall variable level of stainable iron in the obstructed kidney. This reduction in IRP RNA binding activity and ferritin RNA levels suggests the concomitant rise in ferritin expression and iron content in kidney failure is IRP-dependent. In contrast, the reduction in Epo mRNA level in the obstructed kidney was not rescued by genetic ablation of IRP1 suggesting disruption of normal HIF-2a regulation. Furthermore, reduced expression of some HIFa target genes in UUO occurred in the face of increased expression of HIFa proteins and the prolyl hydroxylases (PHD) 2 and PHD1, the latter of which is not known to be HIFa mediated. Our results suggest that the IRP system drives changes in cellular iron metabolism that are associated with kidney failure in UUO but that the impact of IRP on EPO production is overridden by disrupted hypoxia signaling.

MicroRNAs in Human Lymphoblastoid Cell Lines

2012 ◽  
Vol 22 (3) ◽  
pp. 189-196 ◽  
Author(s):  
Sung-Mi Shim ◽  
Hye-Young Nam ◽  
Jae-Eun Lee ◽  
Jun-Woo Kim ◽  
Bok-Ghee Han ◽  
...  
Keyword(s):  
Cell Lines ◽  
Lymphoblastoid Cell Lines ◽  
Human Lymphoblastoid Cell ◽  
Human Lymphoblastoid Cell Lines

Extraction, Chemical Composition, Antioxidant Property and In vitro Anticancer Activity of Silymarin from Silybum Marianum On Kb and A549 Cell Lines

2020 ◽  
Vol 17 ◽  
Author(s):  
Mojgan Azadpour ◽  
Mohammad Mehdi Farajollahi ◽  
Ali Mohammad Varzi ◽  
Pejman Hashemzadeh ◽  
Hossein Mahmoudvand ◽  
...  
Keyword(s):  
Anticancer Activity ◽  
Cell Lines ◽  
A549 Cell ◽  
Hplc Analysis ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Antioxidant Property ◽  
Silybum Marianum ◽  
Stable Free Radical

Introduction: This study aimed to evaluate the antioxidant property of silymarin (SM) extracted from the seed of Silybum marianum and its anticancer activity on KB and A549 cell lines following 24, 48, and 72 h of treatment. Methods: Ten grams of powdered S. marianum seeds were defatted using n-hexane for 6 hours and then extracted by methanol. The silymarin extracted of extraction components The extracted components of silymarin were measured by spectrophotometric assay and HPLC analysis. 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, phenol content, total flavonoid content, and total antioxidant capacity were measured to detect the antioxidant properties of SM. The anticancer activity of the SM on cell lines evaluated by MTT. Results: In HPLC analysis, more than 50% of the peaks were related to silibin A and B. SM was reducedDPPH (the stable free radical) with a 50% inhibitory concentration (IC50) of 6.56 μg/ ml in comparison with butylated hydroxyl toluene (BHT), which indicated an IC50 of ~3.9 μg/ ml.The cytotoxicity effect of SM on the cell lines was studied by MTT assay. The cytotoxicity effect of the extracted silymarin on KB and A549 cell lines was observed up to 80 and 70% at 156 and 78 µg/ml, respectively. The IC50 value of the extracted SM on KB and A549 cell lines after 24 hours of treatment was seen at 555 and 511 µg/ml, respectively. Conclusion: Due to the good antioxidant and anticancer properties of the isolated silymarin, its use as an anticancer drug is suggested.

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