Abstract 5697: Cellular iron depletion weakens isothiocyanate-induced HO-1 upregulation

2010 ◽  
Author(s):  
George Loo
Keyword(s):  
Iron Depletion ◽  
Cellular Iron

scholarly journals Unexpected Link between Iron and Drug Resistance of Candida spp.: Iron Depletion Enhances Membrane Fluidity and Drug Diffusion, Leading to Drug-Susceptible Cells

2006 ◽  
Vol 50 (11) ◽  
pp. 3597-3606 ◽  
Author(s):  
Tulika Prasad ◽  
Aparna Chandra ◽  
Chinmay K. Mukhopadhyay ◽  
Rajendra Prasad
Keyword(s):  
Multidrug Resistance ◽  
Membrane Fluidity ◽  
Iron Uptake ◽  
Efflux Pump ◽  
Disulfonic Acid ◽  
Candida Spp ◽  
Copper Transporter ◽  
Iron Depletion ◽  
Cellular Iron ◽  
Increased Sensitivity

ABSTRACT Inthis study, we show that iron depletion in Candida albicans with bathophenanthrolene disulfonic acid and ferrozine as chelators enhanced its sensitivity to several drugs, including the most common antifungal, fluconazole (FLC). Several other species of Candida also displayed increased sensitivity to FLC because of iron restriction. Iron uptake mutations, namely,Δ ftr1 and Δftr2, as well as the copper transporter mutation Δccc2, which affects high-affinity iron uptake in Candida, produced increased sensitivity to FLC compared to that of the wild type. The effect of iron depletion on drug sensitivity appeared to be independent of the efflux pump proteins Cdr1p and Cdr2p. We found that iron deprivation led to lowering of membrane ergosterol by 15 to 30%. Subsequently, fluorescence polarization measurements also revealed that iron-restricted Candida cells displayed a 29 to 40% increase in membrane fluidity, resulting in enhanced passive diffusion of the drugs. Northern blot assays revealed that the ERG11 gene was considerably down regulated in iron-deprived cells, which might account for the lowered ergosterol content. Our results show a close relationship between cellular iron and drug susceptibilities of C. albicans. Considering that multidrug resistance is a manifestation of multifactorial phenomena, the influence of cellular iron on the drug susceptibilities of Candida suggests iron as yet another novel determinant of multidrug resistance.

scholarly journals Cellular Iron Depletion and the Mechanisms Involved in the Iron-dependent Regulation of the Growth Arrest and DNA Damage Family of Genes

2011 ◽  
Vol 286 (41) ◽  
pp. 35396-35406 ◽  
Author(s):  
Federica Saletta ◽  
Yohan Suryo Rahmanto ◽  
Aritee R. Siafakas ◽  
Des R. Richardson
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Arrest ◽  
Family Members ◽  
Growth Arrest ◽  
Regulatory Elements ◽  
Mrna Levels ◽  
Iron Depletion ◽  
Cellular Iron ◽  
Cycle Arrest

Iron plays a crucial part in proliferation while iron deficiency results in G1/S arrest, DNA damage, and apoptosis. However, the precise role of iron in cell cycle control remains unclear. We showed that iron depletion using the iron chelators, desferrioxamine (DFO), or 2-hydroxy-1-napthylaldehyde isonicotinoyl hydrazone (311), increased the mRNA levels of the growth arrest and DNA damage 45α gene, GADD45α (Darnell, G. and Richardson, D. R. (1999) Blood 94, 781–792). In this study, we examined the effect of iron depletion on up-regulating GADD family members involved in growth control, including cell cycle arrest, apoptosis, and DNA repair, making them therapeutic targets for tumor suppression. We showed the GADD family members were up-regulated by cellular iron depletion. Further, up-regulation of GADD45α after iron deprivation was independent of hypoxia-inducible factor-1α (HIF-1α), octamer-1 (Oct-1), p53 and early growth response 1 (Egr1). We then analyzed the regulatory elements responsible for iron depletion-mediated regulation of GADD45α and identified the specific transcription factor/s involved. This region was within −117 bp and −81 bp relative to the start codon where the consensus sequences of three transcription factors are located: the CCAAT-binding factor/nuclear factor-Y (NF-Y), the stabilizing molecule v-MYB and the enhancer, CCAAT enhancer-binding protein (CEBPα). Mutation analysis, shRNA studies, Western blotting, and electrophoretic mobility shift assays led to the identification of NF-Y in the transcriptional up-regulation of GADD45α after iron depletion. Furthermore, like GADD45α, NF-YA was up-regulated after iron chelation and down-regulated by iron supplementation. These results are important for understanding the mechanisms of iron depletion-mediated cell cycle arrest, DNA damage repair, and apoptosis.

scholarly journals Callyspongiolide kills cells by inducing mitochondrial dysfunction via cellular iron depletion

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Jaeyoung Ha ◽  
Seung Bum Park
Keyword(s):  
Mitochondrial Dysfunction ◽  
Target Identification ◽  
Cancer Therapeutics ◽  
Marine Natural Product ◽  
Great Promise ◽  
Label Free ◽  
Antibody Drug Conjugate ◽  
Iron Depletion ◽  
Cellular Iron ◽  
Lysosomal Dysfunction

AbstractThe highly cytotoxic marine natural product callyspongiolide holds great promise as a warhead of antibody-drug conjugate in cancer therapeutics; however, the mechanism underlying its cytotoxicity remains unclear. To elucidate how callyspongiolide kills cells, we employed label-free target identification with thermal stability-shift-based fluorescence difference in two-dimensional (2-D) gel electrophoresis (TS-FITGE), which allowed observation of a unique phenomenon of protein-spot separation on 2-D gels upon treatment with callyspongiolide at increasing temperatures. During our exploration of what proteins were associated with this phenomenon as well as why it happens, we found that callyspongiolide induces mitochondrial/lysosomal dysfunction and autophagy inhibition. Moreover, molecular biology studies revealed that callyspongiolide causes lysosomal dysfunction, which induces cellular iron depletion and leads to mitochondrial dysfunction and subsequent cytotoxicity. Notably, these effects were rescued through iron supplementation. Although our approach was unable to reveal the direct protein targets of callyspongiolide, unique phenomena observed only by TS-FITGE provided critical insight into the mechanism of action of callyspongiolide and specifically its cytotoxic activity via induction of mitochondrial dysfunction through cellular iron depletion caused by lysosomal deacidification, which occurred independent of known programmed cell death pathways.

Inhibition of HIV-1 by Ferroprotin Expression.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1464-1464
Author(s):  
Sergei Nekhai ◽  
Altreisha Foster ◽  
Min Xu ◽  
Xiaomei Niu ◽  
Jamie Rotimi ◽  
...  
Keyword(s):  
Viral Replication ◽  
Ferritin Level ◽  
Subsequent Treatment ◽  
Iron Chelators ◽  
Wild Type ◽  
Intracellular Iron ◽  
Iron Depletion ◽  
Hepcidin Expression ◽  
Cellular Iron ◽  
Hiv 1

Abstract HIV-1 transcription is induced by viral Tat protein, which recruits transcriptional co-activators to the HIV-1 promoter. We recently showed that Tat is phosphorylated in the Ser16 and Ser 46 residues by protein kinase CDK2 and that mutations in these residues prevent HIV-1 transcription and viral replication [1]. We also found that iron depletion by iron chelators inhibits cellular activity of CDK2, prevents Tat phosphorylation and inhibits HIV-1 transcription [2]. Thus our previous studies suggest that a decrease in cellular iron might have a protective effect against HIV-1 through inhibition of CDK2 and Tat phosphorylation. Here, we analyzed the effect of the iron exporter, ferroportin, on HIV-1 transcription and viral replication. Increased expression of ferroportin by transfection in iron-treated 293T cells significantly reduced ferritin protein levels compared to increased expression of CD4 or EGFP in iron-treated cells as controls. Treatment with hepcidin increased ferritin levels in 293T cells that expressed wild type ferroportin but not the C326Y mutant of ferroprotin which is not sensitive to hepcidin. Expression of both wild type ferroportin and the C326Y mutant in 293T cells significantly inhibited HIV-1 transcription. Treatment with hepcidin partially restored HIV-1 transcription in the cells expressing wild type ferroportin and not in those expressing the C326Y mutant of ferroportin. Treatment of promonocytic THP-1 cells with iron increased cellular ferritin level. Subsequent treatment with phorbol myristate acetate (PMA) led to increased expression of ferroportin and reduced ferritin level, and this reduction in ferritin was partially alleviated by exposing the cells to hepcidin. Thus, PMA appeared to reduce intracellular iron through increased iron export by ferroportin. HIV-1 replication in iron-supplemented THP-1 cells or primary human monocytes was significantly reduced by treatment with PMA. Subsequent exposure of the PMA-treated monocytes to hepcidin partially restored HIV-1 replication, suggesting that HIV-1 was inhibited in part by the expression of ferroportin and its associated iron-exporting activity. Taken together, our results indicate that expression of ferroportin leads to reduction of cellular iron and also reduced HIV-1 transcription and replication, and that exposure to hepcidin may lead to increased cellular iron content and enhancement of HIV-1 replication. Thus our results suggest that iron depletion of cells that harbor HIV might serve as a strategy to combat this infection, and they point to the need to develop iron chelators specifically designed for HIV-1 therapy.

Cellular Iron Homeostasis and Therapeutic Implications of Iron Chelators in Cancer

2014 ◽  
Vol 15 (12) ◽  
pp. 1125-1140 ◽  
Author(s):  
Mohsin Raza ◽  
Sankalpa Chakraborty ◽  
Monjoy Choudhury ◽  
Prahlad Ghosh ◽  
Alo Nag
Keyword(s):  
Iron Homeostasis ◽  
Iron Chelators ◽  
Therapeutic Implications ◽  
Cellular Iron ◽  
Cellular Iron Homeostasis

Non-Anemic Iron Depletion, Oral Iron Supplementation and Indices of Copper Status in College-Aged Females

2002 ◽  
Vol 21 (6) ◽  
pp. 545-552 ◽  
Author(s):  
Sareen S. Gropper ◽  
D. Michele Bader-Crowe ◽  
Lisa S. McAnulty ◽  
B. Douglas White ◽  
Robert E. Keith
Keyword(s):  
Iron Supplementation ◽  
Oral Iron ◽  
Iron Depletion ◽  
Copper Status

scholarly journals Expression Patterns in Reductive Iron Assimilation and Functional Consequences during Phagocytosis of Lichtheimia corymbifera, an Emerging Cause of Mucormycosis

2021 ◽  
Vol 7 (4) ◽  
pp. 272
Author(s):  
Felicia Adelina Stanford ◽  
Nina Matthias ◽  
Zoltán Cseresnyés ◽  
Marc Thilo Figge ◽  
Mohamed I. Abdelwahab Hassan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Iron Uptake ◽  
Intracellular Transport ◽  
Pathogenic Fungus ◽  
Expression Patterns ◽  
Iron Depletion ◽  
Iron Assimilation ◽  
Human Pathogenic Fungus ◽  
Hyphal Formation ◽  
Yeast Mutants

Iron is an essential micronutrient for most organisms and fungi are no exception. Iron uptake by fungi is facilitated by receptor-mediated internalization of siderophores, heme and reductive iron assimilation (RIA). The RIA employs three protein groups: (i) the ferric reductases (Fre5 proteins), (ii) the multicopper ferroxidases (Fet3) and (iii) the high-affinity iron permeases (Ftr1). Phenotyping under different iron concentrations revealed detrimental effects on spore swelling and hyphal formation under iron depletion, but yeast-like morphology under iron excess. Since access to iron is limited during pathogenesis, pathogens are placed under stress due to nutrient limitations. To combat this, gene duplication and differential gene expression of key iron uptake genes are utilized to acquire iron against the deleterious effects of iron depletion. In the genome of the human pathogenic fungus L. corymbifera, three, four and three copies were identified for FRE5, FTR1 and FET3 genes, respectively. As in other fungi, FET3 and FTR1 are syntenic and co-expressed in L. corymbifera. Expression of FRE5, FTR1 and FET3 genes is highly up-regulated during iron limitation (Fe-), but lower during iron excess (Fe+). Fe- dependent upregulation of gene expression takes place in LcFRE5 II and III, LcFTR1 I and II, as well as LcFET3 I and II suggesting a functional role in pathogenesis. The syntenic LcFTR1 I–LcFET3 I gene pair is co-expressed during germination, whereas LcFTR1 II- LcFET3 II is co-expressed during hyphal proliferation. LcFTR1 I, II and IV were overexpressed in Saccharomyces cerevisiae to represent high and moderate expression of intracellular transport of Fe3+, respectively. Challenge of macrophages with the yeast mutants revealed no obvious role for LcFTR1 I, but possible functions of LcFTR1 II and IVs in recognition by macrophages. RIA expression pattern was used for a new model of interaction between L. corymbifera and macrophages.

Sign in / Sign up

Export Citation Format

Share Document