Does Hepatic Hepcidin Play an Important Role in Exercise-Associated Anemia in Rats?

2011 ◽  
Vol 21 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Yu-Qian Liu ◽  
Yan-Zhong Chang ◽  
Bin Zhao ◽  
Hai-Tao Wang ◽  
Xiang-Lin Duan
Keyword(s):  
Regulatory Mechanism ◽  
Iron Absorption ◽  
White Blood Cells ◽  
Strenuous Exercise ◽  
Enzyme Linked Immunosorbent Assay ◽  
Control Group ◽  
Transcriptional Level ◽  
Divalent Metal Transporter 1 ◽  
Divalent Metal Transporter ◽  
Sports Anemia

Some athletes are diagnosed as suffering from sports anemia because of iron deficiency, but the regulatory mechanism remains poorly understood. It is reported that hepcidin may provide a way to illuminate the regulatory mechanism of exercise-associated anemia. Here the authors investigate the hepcidin-involved iron absorption in exercise-associated anemia. Twelve male Wistar rats (300 ± 10 g) were randomly divided into 2 groups, 6 in a control group (CG) and 6 in an exercise group (EG, 5 wk treadmill exercise of different intensities with progressive loading). Serum samples were analyzed for circulating levels of IL-6 by means of enzyme-linked immunosorbent assay (ELISA). The expression of hepatic hepcidin mRNA was examined by real-time polymerase chain reaction analysis. The protein levels of divalent metal transporter 1 (DMT1), ferroportin1 (FPN1), and heme-carrier protein 1 (HCP1) of duodenum epithelium were examined by Western blot. The results showed that the amount of iron and ferritin in serum were lower in EG than in CG (p < .05). The levels of IL-6 and white blood cells were greater in EG than in CG (p < .01). The expression of DMT1, HCP1, and FPN1 was significantly lower in EG than in CG (p < .01). The mRNA expressions of hepatic hepcidin and hemojuvelin in skeletal muscle were remarkably higher in EG than in CG. The data indicated that inflammation was induced by strenuous exercise, and as a result, the transcriptional level of the hepatic hepcidin gene was increased, which further inhibited the expression of iron-absorption proteins and led to exercise-associated anemia.

scholarly journals Increased DMT1 and FPN1 expression with enhanced iron absorption in ulcerative colitis human colon

2020 ◽  
Vol 318 (2) ◽  
pp. C263-C271 ◽  
Author(s):  
Emily A. Minor ◽  
Justin T. Kupec ◽  
Andrew J. Nickerson ◽  
Karthikeyan Narayanan ◽  
Vazhaikkurichi M. Rajendran
Keyword(s):  
Ulcerative Colitis ◽  
Iron Deficiency ◽  
Iron Absorption ◽  
Basolateral Membrane ◽  
Specific Inhibitor ◽  
Distal Colon ◽  
Human Colon ◽  
Deficiency Anemia ◽  
Divalent Metal Transporter 1 ◽  
Divalent Metal Transporter

Iron deficiency anemia is a common complication of ulcerative colitis (UC) that can profoundly impact quality of life. Most iron absorption occurs in the duodenum via divalent metal transporter 1 (DMT1)-mediated uptake and ferroportin-1 (FPN1)-mediated export across the apical and basolateral membranes, respectively. However, the colon also contains iron transporters and can participate in iron absorption. Studies have shown increased duodenal DMT1 and FPN1 in patients with UC, but there is conflicting evidence about whether expression is altered in UC colon. We hypothesized that expression of colonic DMT1 and FPN1 will also increase to compensate for iron deficiency. Quantitative RT-PCR and Western blot analyses were performed on duodenal and colonic segmental (right colon, transverse colon, left colon, and rectum) biopsies obtained during colonoscopy. DMT1 mRNA and protein abundances in colonic segments were approximately equal to those in the duodenum, whereas colonic FPN1 mRNA and protein abundances of colonic segments were about one-quarter of those of the duodenum. DMT1 specific mRNA and protein abundances were increased twofold, whereas FPN1 mRNA and protein expressions were increased fivefold in UC distal colon. Immunofluorescence studies revealed enhanced expression of apical membrane- and basolateral membrane-localized DMT1 and FPN1 in UC human colon, respectively. Increased DMT1 expression was associated with enhanced 2-(3-carbamimidoylsulfanylmethyl-benzyl)-isothiourea (CISMBI, DMT1 specific inhibitor)-sensitive 59Fe uptake in UC human colon. We conclude from these results that patients with active UC have increased expression of colonic iron transporters and increased iron absorption, which may be targeted in the treatment of UC-related anemia.

Relationship between intestinal iron-transporter expression, hepatic hepcidin levels and the control of iron absorption

2002 ◽  
Vol 30 (4) ◽  
pp. 724-726 ◽  
Author(s):  
G.J. Anderson ◽  
D. M. Frazer ◽  
S.J. Wilkins ◽  
E. M. Becker ◽  
K. N. Millard ◽  
...  
Keyword(s):  
Iron Transport ◽  
Iron Absorption ◽  
Negative Regulator ◽  
Deficient Diet ◽  
Divalent Metal Transporter 1 ◽  
Intestinal Iron Absorption ◽  
Divalent Metal Transporter ◽  
Hepcidin Expression ◽  
Iron Deficient ◽  
Transport Molecules

Hepcidin is an anti-microbial peptide predicted to be involved in the regulation of intestinal iron absorption. We have examined the relationship between the expression of hepcidin in the liver and the expression of the iron-transport molecules divalent-metal transporter 1, duodenal cytochrome b, hephaestin and Ireg1 in the duodenum of rats switched from an iron-replete to an iron-deficient diet or treated to induce an acute phase response. In each case, elevated hepcidin expression correlated with reduced iron absorption and depressed levels of iron-transport molecules. These data are consistent with hepcidin playing a role as a negative regulator of intestinal iron absorption.

Iron supply determines apical/basolateral membrane distribution of intestinal iron transporters DMT1 and ferroportin 1

2010 ◽  
Vol 298 (3) ◽  
pp. C477-C485 ◽  
Author(s):  
Marco T. Núñez ◽  
Victoria Tapia ◽  
Alejandro Rojas ◽  
Pabla Aguirre ◽  
Francisco Gómez ◽  
...  
Keyword(s):  
Translational Regulation ◽  
Fluorescent Protein ◽  
Iron Absorption ◽  
Iron Status ◽  
Basolateral Membrane ◽  
Membrane Domains ◽  
Divalent Metal Transporter 1 ◽  
Intestinal Iron Absorption ◽  
Divalent Metal Transporter ◽  
Iron Supply

Intestinal iron absorption comprises the coordinated activity of the influx transporter divalent metal transporter 1 (DMT1) and the efflux transporter ferroportin (FPN). In this work, we studied the movement of DMT1 and FPN between cellular compartments as a function of iron supply. In rat duodenum, iron gavage resulted in the relocation of DMT1 to basal domains and the internalization of basolateral FPN. Considerable FPN was also found in apical domains. In Caco-2 cells, the apical-to-basal movement of cyan fluorescent protein-tagged DMT1 was complete 90 min after the addition of iron. Steady-state membrane localization studies in Caco-2 cells revealed that iron status determined the apical/basolateral membrane distribution of DMT1 and FPN. In agreement with the membrane distribution of the transporters,55Fe flux experiments revealed inward and outward iron fluxes at both membrane domains. Antisense oligonucleotides targeted to DMT1 or FPN inhibited basolateral iron uptake and apical iron efflux, respectively, indicating the participation of DMT1 and FPN in these fluxes. The fluxes were regulated by the iron supply; increased iron reduced apical uptake and basal efflux and increased basal uptake and apical efflux. These findings suggest a novel mechanism of regulation of intestinal iron absorption based on inward and outward fluxes at both membrane domains, and repositioning of DMT1 and FPN between membrane and intracellular compartments as a function of iron supply. This mechanism should be complementary to those based in the transcriptional or translational regulation of iron transport proteins.

Effect of DMT1 Mutations at Birth and in the First Years of Life.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3586-3586
Author(s):  
Iolascon Achille ◽  
d’Apolito Maria ◽  
Servedio Veronica ◽  
De Falco Luigia ◽  
Piga Antonio ◽  
...  
Keyword(s):  
Iron Overload ◽  
Iron Uptake ◽  
Iron Absorption ◽  
Transferrin Saturation ◽  
Adult Life ◽  
Microcytic Anemia ◽  
Hepatic Iron ◽  
Liver Iron ◽  
Divalent Metal Transporter 1 ◽  
Divalent Metal Transporter

Abstract Divalent metal transporter 1 (DMT1) is involved in dietary iron uptake on the luminal side of duodenal enterocytes and transfers iron from the endosome to the cytosol in the marrow erythroblasts. Spontaneous (mk mice and Belgrade rats) or acquired (DMT1 -/- mice) inactivation of DMT1 in rodents produces a severe microcytic anemia at birth, caused by inefficient intestinal iron absorption and defective iron utilization in erythroid cells. The first reported patient with DMT1 mutations had microcytic anemia and iron overload in adult life. We here report the hematological phenotype of a newborn with a severe mycrocytic anemia (Hb 4 g/dL, MCV 71 fL) at birth and during the first months of life. Serum iron, transferrin saturation and serum ferritin were 160 microg/L, 100% and 846 ng/ml respectively at 3 months of age. Hepatic iron overload wad documented at the age of 5 years by both non invasive SQUID and liver biopsy. Sequence analysis of genomic DNA of the family revealed that the child was compound heterozygote for two novel DMT1 mutations, inherited by the asymptomatic parents. The first change deleted 3 bp (c.310 - 3_5del CTT) in intron 4 resulting in a splicing abnormality and the skipping of exon 5. The second was C&gt;T 1246 substitution that causes arginine &gt; cysteine replacement at position 416 (p. R416C) in the protein. This missense affects an highly conserved residue in one of the putative transmembrane domains. A striking reduction of the protein in peripheral blood cells of the proband was demonstrated by western blot using an anti-DMT1 antibody. The child required blood transfusions at birth and in the first two months of life. Thereafter, treatment with subcutaneous erythropoietin mantained hemoglobin levels between 7.5–9.5 g/dL, allowing transfusion-independence. The haematological phenotype of this patient highlights the essential role of DMT1 in erythropoiesis. The early and significant hepatic iron accumulation indicates that, as in animal models, DMT1 is dispensable for liver iron uptake. Finally DMT1 inactivation in the gut is likely bypassed by other pathways of iron absorption.

Kinetic of Iron Absorption and Expression of Iron Related Genes in Beta-Thalassemia.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3846-3846
Author(s):  
Laura Breda ◽  
Sara Gardenghi ◽  
Ella Guy ◽  
Ninette Amariglio ◽  
Konstantin Adamsky ◽  
...  
Keyword(s):  
Iron Overload ◽  
Iron Content ◽  
Iron Absorption ◽  
Globin Gene ◽  
Active Form ◽  
Beta Thalassemia ◽  
Post Transplantation ◽  
Divalent Metal Transporter 1 ◽  
Hematopoietic Stem ◽  
Divalent Metal Transporter

Abstract We generated the first transplantable adult mouse models of beta-thalassemia intermedia and major by infusing mouse hematopoietic-fetal-liver cells (HFLC) heterozygous or homozygous for a deletion of the beta-globin gene (respectively with th3/+ and th3/th3 cells) into lethally irradiated congenic C57BL/6 mice. Six to 8 weeks post transplantation, mice transplanted with th3/+ HFLCs show 7 to 9 g/dL of hemoglobin levels, splenomegaly, abnormal red cells and increased iron overload. Mice transplanted with th3/th3 HFLCs, unless blood transfused, die 8 to 10 weeks after engraftment showing profound anemia, massive splenomegaly and very rapid and dramatic iron overload. For this reason, we began a systematic study to compare iron content and the expression level of iron related genes in normal and thalassemic mice of varying ages and sex in different organs (liver, duodenum, spleen, kidney and heart). In liver, we observed that iron content increases proportionally with the level of anemia, age and if the blood transfusion is included. We are currently analyzing the other organs. The expression of hepcidin, ferroportin, Hfe, ferritin, transferrin, transferrin-receptor 1 and 2, ceruloplasmin, divalent metal transporter 1 and hemojuvelin are being tested also in all these organs. In particular, we observed that hepcidin is dramatically downregulated in liver of beta-thalassemic animals. Our hypothesis is that low expression of this gene leads to high iron content in these animals. We intend to demonstrate that administration or increasing hepcidin levels of this peptide can prevent iron absorption in beta-thalassemia. We developed two alternative strategies to test our hypothesis. In the first one, we synthesized the active form of the mouse hepcidin peptide that will be administered intraperitoneally to mice affected by beta-thalassemia. In the second, lentiviral vectors have been generated in order to constitutively secrete hepcidin in the bloodstream of animals affected by beta-thalassemia. These vectors were introduced into hematopoietic stem cells derived from mouse embryos of normal and mice affected by beta-thalassemia and engrafted in myeolablated normal mice. The engrafted mice express hepcidin 6 weeks post transplantation by RT PCR. These animals, along with the animals in which hepcidin will be administrated intraperitoneally, will be analyzed at the endpoint of the experiment (&gt; 4 months) for their hematological values and iron content to see if the use of hepcidin can be used to prevent excessive iron absorption in beta-thalassemia.

Iron Imports. V. Transport of iron through the intestinal epithelium

2006 ◽  
Vol 290 (3) ◽  
pp. G417-G422 ◽  
Author(s):  
Yuxiang Ma ◽  
Mary Yeh ◽  
Kwo-yih Yeh ◽  
Jonathan Glass
Keyword(s):  
Iron Transport ◽  
Brush Border Membrane ◽  
Iron Absorption ◽  
Basolateral Membrane ◽  
Apical Surface ◽  
Intracellular Iron ◽  
Divalent Metal Transporter 1 ◽  
Divalent Metal Transporter ◽  
Metal Transporter ◽  
Apical Compartment

Iron absorption across the brush-border membrane requires divalent metal transporter 1 (DMT1), whereas ferroportin (FPN) and hephaestin are required for exit across the basolateral membrane. However, how iron passes across the enterocyte is poorly understood. Both chaperones and transcytosis have been postulated to account for intracellular iron transport. With iron feeding, DMT1 undergoes endocytosis and FPN translocates from the apical cytosol to the basolateral membrane. The fluorescent metallosensor calcein offered to the basolateral surface of enterocytes is found in endosomes in the apical compartment, and its fluorescence is quenched when iron is offered to the apical surface. These experiments are consistent with vesicular iron transport as a possible pathway for intracellular iron transport.

Expression of iron-related proteins in the duodenum is up-regulated in patients with chronic inflammatory disorders

2013 ◽  
Vol 111 (6) ◽  
pp. 1059-1068 ◽  
Author(s):  
Abitha Sukumaran ◽  
Jithu James ◽  
Harish Palleti Janardhan ◽  
Anita Amaladas ◽  
Lekshmy Madathilazhikathu Suresh ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Expression ◽  
Control Group ◽  
Divalent Metal Transporter 1 ◽  
Divalent Metal Transporter ◽  
Inflammatory Disorders ◽  
Inflammatory Conditions ◽  
Gene And Protein Expression ◽  
Fe Homeostasis ◽  
Related Proteins

Mechanisms responsible for derangements in Fe homeostasis in chronic inflammatory conditions are not entirely clear. The aim of the present study was to test the hypothesis that inflammation affects the expression of Fe-related proteins in the duodenum and monocytes of patients with chronic inflammatory disorders, thus contributing to dysregulated Fe homeostasis. Duodenal mucosal samples and peripheral blood monocytes obtained from patients with chronic inflammatory disorders, namely ulcerative colitis (UC), Crohn's disease (CD) and rheumatoid arthritis, were used for gene and protein expression studies. Hb levels were significantly lower and serum C-reactive protein levels were significantly higher in patients in the disease groups. The gene expression of several Fe-related proteins in the duodenum was significantly up-regulated in patients with UC and CD. In patients with UC, the protein expression of divalent metal transporter 1 and ferroportin, which are involved in the absorption of dietary non-haem Fe, was also found to be significantly higher in the duodenal mucosa. The gene expression of the duodenal proteins of interest correlated positively with one another and negatively with Hb. In patients with UC, the gene expression of Fe-related proteins in monocytes was found to be unaffected. In a separate group of patients with UC, serum hepcidin levels were found to be significantly lower than those in the control group. In conclusion, the expression of Fe-related proteins was up-regulated in the duodenum of patients with chronic inflammatory conditions in the present study. The effects appeared to be secondary to anaemia and the consequent erythropoietic drive.

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