scholarly journals Iron feeding induces ferroportin 1 and hephaestin migration and interaction in rat duodenal epithelium

2009 ◽  
Vol 296 (1) ◽  
pp. G55-G65 ◽  
Author(s):  
Kwo-yih Yeh ◽  
Mary Yeh ◽  
Laura Mims ◽  
Jonathan Glass
Keyword(s):  
Brush Border Membrane ◽  
Iron Absorption ◽  
Basolateral Membrane ◽  
Hek293 Cells ◽  
Velocity Sedimentation ◽  
Cell Sheets ◽  
Ferroportin 1 ◽  
Sds Page ◽  
Duodenal Epithelium ◽  
Blue Native

Intestinal iron absorption involves proteins located in the brush border membrane (BBM), cytoplasm, and basolateral membrane (BLM) of duodenal enterocytes. Ferroportin 1 (FPN1) and hephaestin (Heph) are necessary for transport of iron out of enterocytes, but it is not known whether these two proteins interact during iron absorption. We first examined colocalization of the proteins by cotransfection of HEK293 cells with pDsRed-FPN1 with pEmGFP-Heph or with the COOH-terminal truncated pEmGFP-HephΔ43 or -HephΔ685 and found that FPN1 and Heph with or without the COOH terminus colocalized. In rat duodenal enterocytes, within 1 h of iron feeding prominent migration of FPN1 from the apical subterminal zone to the basal subnuclear zone of the BLM occurred and increased to at least 4 h after feeding. Heph exhibited a similar though less prominent migration after iron ingestion. Analysis using rat duodenal epithelial cell sheets demonstrated that 1) by velocity sedimentation ultracentrifugation, FPN1 and Heph occupied vesicles of different sizes prior to iron feeding and migrated to similar fractions 1 h after iron feeding; 2) by blue native/SDS-PAGE, FPN1, and Heph interacted to form two complexes, one containing dimeric FPN1 and intact Heph and the other consisting of monomeric FPN1 and a Heph fragment; and 3) by immunoprecipitation, anti-Heph or anti-FPN1 antiserum coimmunoprecipitated FPN1 and Heph. Thus the data indicate that FPN1 and Heph migrate and interact during iron feeding and suggest that dimeric FPN1 is associated with intact Heph.

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.

Effect of chronic inflammation on electrolyte transport in rabbit ileal villus and crypt cells

1997 ◽  
Vol 272 (4) ◽  
pp. G732-G741 ◽  
Author(s):  
U. Sundaram ◽  
A. B. West
Keyword(s):  
Chronic Inflammation ◽  
Inflammatory Mediators ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Basolateral Membrane ◽  
Rabbit Model ◽  
Electrolyte Transport ◽  
Acid Load ◽  
Crypt Cells ◽  
Stimulation Of

The effect of chronic inflammation on electrolyte transport in rabbit ileal villus and crypt cells was determined with the use of a rabbit model of chronic ileitis. In both cells, Na+/H+ exchange was monitored by following recovery from an acid load, and Cl-/HCO3- exchange was monitored by following recovery from an alkaline load. In villus cells, recovery from an acid load was not affected; however, recovery from an alkaline load was slowed. These data suggest that chronic inflammation inhibits Cl-/HCO3- exchange in villus cells. In contrast, in crypt cells, recovery from an alkaline load was unaffected, whereas recovery from an acid load was accelerated. These data suggest that chronic inflammation stimulates Na+/H+ exchange in crypt cells. Inhibition of Cl-/HCO3- exchange in villus cells would be expected to inhibit coupled NaCl absorption, which occurs by the coupling of brush-border membrane (BBM) Na+/H+ and Cl-/HCO3- exchange. Stimulation of Na+/H+ exchange in crypt cells, known to be present only on the basolateral membrane, alkalinizes the cell. This alkalinization may stimulate BBM Cl-/HCO3- exchange, resulting in HCO3- secretion. Thus these unique alterations in transporter activity suggest that different endogenous immune-inflammatory mediators may have differing effects on specific transporters in villus and crypt cells in the chronically inflamed ileum.

Comparative Analysis of Cytoplasmic Membrane Proteomes of Escherichia coli Using 2D Blue Native/SDS-PAGE

2010 ◽  
pp. 257-269 ◽  
Author(s):  
Susan Schlegel ◽  
Mirjam Klepsch ◽  
David Wickström ◽  
Samuel Wagner ◽  
Jan-Willem de Gier
Keyword(s):  
Escherichia Coli ◽  
Comparative Analysis ◽  
Cytoplasmic Membrane ◽  
Sds Page ◽  
Blue Native

Proximal tubular dopamine production regulates basolateral Na-K-ATPase

1992 ◽  
Vol 262 (4) ◽  
pp. F566-F571 ◽  
Author(s):  
A. D. Baines ◽  
P. Ho ◽  
R. Drangova
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Sch 23390 ◽  
Basolateral Membrane ◽  
Sodium Dodecyl ◽  
Maximal Activity ◽  
Western Blots ◽  
Salt Diet ◽  
Low Salt ◽  
Proximal Tubular

Regulation of proximal tubular Na-K-adenosine-triphosphatase (ATPase), brush-border membrane Na(+)-H+ antiporter and Na(+)-Pi symporter activity by endogenously produced dopamine was examined in Wistar rats. Na-K-ATPase was measured in basolateral membrane (BLM) fractions permeabilized with alamethicin or sodium dodecyl sulfate (SDS). Carbidopa (5 mg/kg) injected 18 h before removal of kidneys increased maximal activity (Vmax) noncompetitively in cortical BLM but not in other membrane fractions or outer medullary BLM (-2 +/- 4%). Chronic renal denervation did not alter the response. Carbidopa stimulated Na-K-ATPase in cortical BLM from rats eating a normal salt diet with and without 1% saline to drink (+18 +/- 4% and +22 +/- 4%, respectively; P greater than 0.001). Carbidopa did not increase Vmax of BLM Na-K-ATPase from rats eating a low-salt diet (+1.5 +/- 4%); however, when the low-salt diet was supplemented with 1 mM dihydroxyphenylalanine (dopa) to drink for 1 day carbidopa, increased Vmax by 18 +/- 3% (P = 0.018). Carbidopa did not alter the Michaelis constant (Km) for Na or K or inhibitory constant (Ki) for ouabain. Injection of the DA1 antagonist Sch 23390 (2 mg/kg) also increased Na-K-ATPase (18 +/- 4%; P = 0.014). Western blots using a monoclonal alpha-subunit antibody revealed a 22 +/- 8% increase following carbidopa treatment (P = 0.033; n = 19 pairs). Carbidopa had no effect on Na(+)-H+ antiporter activity (22Na uptake) or on Na(+)-32Pi cotransport in brush-border membrane vesicles. These results indicate that dopamine produced in proximal tubules tonically reduces Na-K-ATPase Vmax by decreasing the number of alpha-subunits associated with the BLM.

Characterization of the Consequences of YidC Depletion on the Inner Membrane Proteome of E. coli Using 2D Blue Native/SDS-PAGE

2011 ◽  
Vol 409 (2) ◽  
pp. 124-135 ◽  
Author(s):  
David Wickström ◽  
Samuel Wagner ◽  
Per Simonsson ◽  
Ovidiu Pop ◽  
Louise Baars ◽  
...  
Keyword(s):  
Membrane Proteome ◽  
Inner Membrane ◽  
E Coli ◽  
Sds Page ◽  
Blue Native

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.

High specific activity heme-Fe and its application for studying heme-Fe metabolism in Caco-2 cell monolayers

2002 ◽  
Vol 283 (5) ◽  
pp. G1125-G1131 ◽  
Author(s):  
Jennifer R. Follett ◽  
Yasushi A. Suzuki ◽  
Bo Lönnerdal
Keyword(s):  
Iron Absorption ◽  
Specific Activity ◽  
Iron Status ◽  
Basolateral Membrane ◽  
High Specific Activity ◽  
Heme Iron ◽  
Nonheme Iron ◽  
Serum Free Medium ◽  
Factors Affecting ◽  
Cell Monolayers

Heme-Fe is an important source of dietary iron in humans. Caco-2 cells have been used extensively to study human iron absorption with an emphasis on factors affecting nonheme iron absorption. Therefore, we examined several factors known to affect heme iron absorption. Cells grown in bicameral chambers were incubated with high specific activity [59Fe]heme alone or with 1% globin, BSA, or fatty acid-free BSA (BSA-FA) to examine the effect of protein source on absorption. Heme iron absorption was enhanced by globin and inhibited by BSA and BSA-FA. Absorption of heme iron in cells pretreated for 7 days with serum-free medium containing 1, 25, 50, or 100 μM Fe was higher in the 1-μM-Fe pretreatment group than in all other groups ( P < 0.05), showing an effect of iron status. Increased heme concentrations resulted in decreased percent absorbed but increased total heme iron absorption and increased transport rate across the basolateral membrane. Finally, cells treated with 10 μM CdCl2, which induces heme oxygenase, demonstrated higher absorption of [59Fe]heme than control cells ( P < 0.05). Our results from Caco-2 cells are in agreement with human studies and make this a promising model for examining intestinal heme iron absorption.

Sign in / Sign up

Export Citation Format

Share Document