Transferrin protein and iron uptake by cultured rat fibroblasts

Octave, Jean‐Noël; Schneider, Yves‐Jacques; Hoffmann, Pierre; Trouet, André; Crichton, Robert R.

doi:10.1016/0014-5793(79)81193-x

Cited by 70 publications

(17 citation statements)

References 12 publications

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“…Similar activity has been noted in a number of other cell types, including mammalian endothelial cells and macrophages (4,6,21,25,27,28,30,40,43,52). Previous work has shown that CQ treatment can alter vacuolar pH in yeast (42).…”

Section: Discussionsupporting

confidence: 67%

Relationship between Chloroquine Toxicity and Iron Acquisition in Saccharomyces cerevisiae

Emerson

Nau

Martin³

et al. 2002

Antimicrob Agents Chemother

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Chloroquine is one of the most effective antimalarials, but resistance to it is becoming widespread. However, we do not fully understand either the drug's mode of action or the mechanism of resistance. In an effort to expand our understanding of the mechanism of action and resistance associated with chloroquine, we used Saccharomyces cerevisiae as a model eukaryotic system. To aid in the discovery of potential drug targets we applied the transcriptional profiling method to identify genes transcriptionally responsive to chloroquine treatment in S. cerevisiae. Among the genes that were differentially expressed with chloroquine treatment were a number of metal transporters involved in iron acquisition (SIT1, ARN2, ARN4, and SMF2). These genes exhibit similar expression patterns, and several are known to be regulated by AFT1, a DNA binding protein, which responds to iron levels in the cell. We investigated the role of chloroquine in iron metabolism by using a variety of approaches, including pharmacological, genetic, and biochemical techniques. For these experiments, we utilized yeast lacking the major iron uptake pathways (FET3 and FET4) and yeast deficient in SIT1, encoding the major up-regulated iron siderophore transporter. Our experiments show that yeast genetically or environmentally limited in iron availability has increased sensitivity to chloroquine in pharmacological assays and that the addition of iron rescues these cells from chloroquine killing.55 FeCl 3 accumulation was inhibited in the presence of chloroquine, and kinetic analysis demonstrated that inhibition was competitive. These results are consistent with deprivation of iron as a mechanism of chloroquine killing in yeast.Chloroquine (CQ) is commonly used for treatment of malaria; however, its mode of action and the mechanism of resistance are still not fully understood. Better knowledge of CQ's mode of action may make it possible to identify new drugs that target similar pathways or to reverse existing resistant phenotypes.CQ has been shown to interact in both mammalian cells and Plasmodium spp. with a number of different pathways, including changes in vacuolar (or lysosomal) pH (9,22,39,56), binding to DNA and RNA (3,11,41,53), binding to heme and ␤-hematin in Plasmodium falciparum (1, 55; reviewed in reference 20). In the case of P. falciparum, CQ was an effective drug whose efficacy has been severely compromised by the emergence of drug-resistant parasites (8,20).To analyze the mechanism of CQ action, we used transcriptional profiling in a model eukaryotic system, Saccharomyces cerevisiae. Differential transcriptional profiling using microarray analysis is based on detecting differences in expression of mRNAs in cells treated under different conditions. No information other than the genomic sequence and the open reading frame (ORF) predictions is necessary to assay mRNA expression. Such whole-genome analysis allows the determination of expression profiles without preselection of genes. For the experiments described here, we used the Affymetrix...

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Section: Discussionsupporting

confidence: 67%

Relationship between Chloroquine Toxicity and Iron Acquisition in Saccharomyces cerevisiae

Emerson

Nau

Martin³

et al. 2002

Antimicrob Agents Chemother

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“…Once iron enters the labile pool, it is in equilibrium with storage iron protein (ferritin) and iron-containing enzymes (23,29,47). Thus, CHLOR has been found to reduce markedly the release of iron from endocytized HTF in a variety of cell types, including mononuclear phagocytes, without affecting receptor recycling (4,15,44,52).…”

Section: Discussionmentioning

confidence: 99%

“…However, CHLOR has been found to prevent the accumulation of iron in cells incubated with HTF because of its effect on intracellular alkalization (4,15,44,52).…”

Section: Htf Does Not Reverse Chlor Inhibition Of Pb 18 Intracellularmentioning

confidence: 99%

Chloroquine Inhibits Paracoccidioides brasiliensis Survival within Human Monocytes by Limiting the Availability of Intracellular Iron

Dias-Melício

Moreira

Calvi

et al. 2006

Microbiology and Immunology

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Paracoccidioidomycosis is a deep mycosis that is endemic in Latin America. This disease is caused by Paracoccidioides brasiliensis, a fungus that undergoes thermal dimorphism, developing as yeast at body temperature and as a mycelium at room temperature (16). This fungus causes natural infections by inhalation of conidia or mycelial elements. These conidia convert to the parasitic yeast form in the lungs of mice (39). Ingested conidia or yeast-forms of P. brasiliensis readily multiplied inside murine alveolar or peritoneal macrophages; however, if they were activated by cytokines, such as IFN-γ, the multiplication was limited and conidia or yeast cells were killed (5,10). Similarly, the interaction of human phagocytic cells and yeastform of P. brasiliensis was studied in vitro and yeast cells were readily ingested by monocytes or monocytederived macrophages. However, these cells allowed P. brasiliensis multiplication, unless they were activated with IFN-γ or culture supernatants from concanavalin-A-stimulated mononuclear cells, suggesting that this activation could be responsible for iron restriction and the consequent decrease in the survival of P. brasiliensis Abstract: The mechanisms used by Paracoccidioides brasiliensis (Pb 18) to survive into monocytes are not clear. Cellular iron metabolism is of critical importance to the growth of several intracellular pathogens, including P. brasiliensis, whose capacity to multiply in mononuclear phagocytes is dependent on the availability of intracellular iron. Chloroquine, by virtue of its basic properties, has been shown to prevent release of iron from holotransferrin by raising endocytic and lysosomal pH, and thereby interfering with normal iron metabolism. Then, in view of this, we have studied the effects of CHLOR on P. brasiliensis multiplication in human monocytes and its effect on the murine paracoccidioidomycosis. CHLOR induced human monocytes to kill P. brasiliensis. The effect of CHLOR was reversed by FeNTA, an iron compound that is soluble at neutral to alkaline pH, but not by holotransferrin, which releases iron only in an acidic environment. CHLOR treatment of Pb 18-infected BALB/c mice significantly reduced the viable fungi recovery from lungs, during three different periods of evaluation, in a dose-dependent manner. This study demonstrates that iron is of critical importance to the survival of P. brasiliensis yeasts within human monocytes and the CHLOR treatment in vitro induces Pb 18 yeast-killing by monocytes by restricting the availability of intracellular iron. Besides, the CHLOR treatment in vivo significantly reduces the number of organisms in the lungs of Pb-infected mice protecting them from several infections. Thus, CHLOR was effective in the treatment of murine paracoccidioidomycosis, suggesting the potential use of this drug in patients' treatment. Chloroquine Inhibits Paracoccidioides brasiliensis

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“…By contrast, ClPhzC-(CN)2 has no effect on the release of iron from transferrin at concentrations below 50 nmol/l during 30 min incubation, i.e. the uptake of iron from transferrin increases linearly a long time after the mitochondria [44] iron uptake increases by time in excess of transferrin uptake. This Time (rnin) Fig.…”

Section: !Iyandcf Qf Surciizute a Tp Und Metabolic Inhibitors On The mentioning

confidence: 85%

Uptake of Iron from Transferrin by Isolated Rat‐Liver Mitochondria Mediated by Phosphate Compounds

Konopka¹,

Romslo

1980

European Journal of Biochemistry

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1. Isolated rat-liver mitochondria accumulate iron from transferrin at neutral pH by a mechanism which is markedly stimulated by small-molecular-weight polyphosphate compounds. The efficiency of the phosphate compounds decreases in the order: pyrophosphate > ATP > GTP > 2,3-bis-(phospho)glycerate > phosphate.2. The uptake has a very low energy dependence, and it does not depend on the hydrolysis of ATP or the saturation of transferrin, but it increases in parallel to the concentration of iron to reach a saturation level of 800-1200 pmol iron/mg protein.3 . Following a chase with unlabelled transferrin, ('251)-labelled transferrin bound to the mitochondria remains constant, whereas the progressive uptake of 59Fe levels off.4. During reincubation of iron-loaded mitochondria up to 30% of the iron is mobilized in the presence of ascorbate and ATP (or apotransferrin).5. The results suggest that iron is mobilized from transferrin by the polyphosphate compounds outside the mitochondria and taken up by the mitochondria in a subsequent reaction.The ferrochelatase reaction represents the ultimate destination for the major part of iron entering the cell. Although it has been claimed that the ferrochelatase resides in part [l] or exclusively in the cytosol [2] most investigators agree that the ferrochelatase is a particulate enzyme confined to the mitochondria [3-51, tentatively on the M-side of the inner membrane [6-81 and depending on unsaturated phospholipids for full activity [9]. Hence, to reach the ferrochelatase iron has to penetrate the mitochondria1 membrane systems.The mechanism(s) by means of which iron is transported across the cytosol, from the plasma membrane to the mitochondria is largely unknown, as is the nature of the cytosol iron-binding ligands. Controversy exists as to whether iron is released from transferrin at the plasma membrane [lo, to operate on the main pathway of iron to the niitochondria in vivo. The uptake of iron by isolated mitochondria has been described, using iron-ATP [18], iron-hydroxyquinoline [19] or iron-sucrose [20] as the iron donor compound. A coherent picture, however, has not emerged.The importance of transferrin as an iron-donor directly to the mitochondria has been emphasized [14,16]. As yet, however, there are only a few studies dealing with the utilization of transferrin iron by isolated mitochondria. Barnes et al. [21] concluded from experiments with sonicated mitochondria that neither transferrin not ferritin functioned as substrate to the ferrochelatase reaction. Ulvik et al. [22] and Koller et al. [23] found that iron was mobilized from transferrin by a mechanism sensitive to uncoupler, high pH and haemin. The release process operated at a rate below that necessary to cope with the ferrochelatase and also at a pH outside that occurring in vivo. It was concluded that transferrin was not a suitable donor of iron to mitochondria. More recently, Konopka [24] and Konopka and Turska [25] reported that rat liver mitochondria accumulated iron from transferrin at a signifi...

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Transferrin protein and iron uptake by cultured rat fibroblasts

Cited by 70 publications

References 12 publications

Relationship between Chloroquine Toxicity and Iron Acquisition in Saccharomyces cerevisiae

Relationship between Chloroquine Toxicity and Iron Acquisition in Saccharomyces cerevisiae

Chloroquine Inhibits Paracoccidioides brasiliensis Survival within Human Monocytes by Limiting the Availability of Intracellular Iron

Uptake of Iron from Transferrin by Isolated Rat‐Liver Mitochondria Mediated by Phosphate Compounds

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