Inhibitory Effect of Calcium on Non-heme Iron Absorption May Be Related to Trans location of DMT-1 at the Apical Membrane of Enterocytes

TY - JOUR

T1 - Inhibitory Effect of Calcium on Non-heme Iron Absorption May Be Related to Trans location of DMT-1 at the Apical Membrane of Enterocytes

AU - Thompson, Ben A. V.

AU - Sharp, Paul A.

AU - Elliott, Ruan

AU - Fairweather-Tait, Susan J.

PY - 2010/7/28

Y1 - 2010/7/28

N2 - Many studies show that calcium reduces iron absorption from single meals, but the underlying mechanism is not known. We tested the hypothesis that calcium alters the expression and/or functionality of iron transport proteins. Differentiated Caco-2 cells were treated with ferric ammonium citrate and calcium chloride, and ferritin, DMT-1, and ferroportin were quantified in whole-cell lysate and cell-membrane fractions. Calcium attenuated the iron-induced increase in cell ferritin levels in a dose-dependent manner; a significant decrease was seen at calcium concentrations of 1.25 and 2.5 mM but was only evident after a 16-24 h incubation period. Calcium and iron treatments decreased DMT-1 protein in Caco-2 cell membranes, although total DMT-1 in whole cell lysates was unchanged by either iron or calcium. No change was seen in ferroportin expression. Our data suggest that calcium reduces iron bioavailability by decreasing DMT-1 expression at the apical cell membrane, thereby downregulating iron transport into the cell.

AB - Many studies show that calcium reduces iron absorption from single meals, but the underlying mechanism is not known. We tested the hypothesis that calcium alters the expression and/or functionality of iron transport proteins. Differentiated Caco-2 cells were treated with ferric ammonium citrate and calcium chloride, and ferritin, DMT-1, and ferroportin were quantified in whole-cell lysate and cell-membrane fractions. Calcium attenuated the iron-induced increase in cell ferritin levels in a dose-dependent manner; a significant decrease was seen at calcium concentrations of 1.25 and 2.5 mM but was only evident after a 16-24 h incubation period. Calcium and iron treatments decreased DMT-1 protein in Caco-2 cell membranes, although total DMT-1 in whole cell lysates was unchanged by either iron or calcium. No change was seen in ferroportin expression. Our data suggest that calcium reduces iron bioavailability by decreasing DMT-1 expression at the apical cell membrane, thereby downregulating iron transport into the cell.

U2 - 10.1021/jf101388z

DO - 10.1021/jf101388z

M3 - Article

VL - 58

SP - 8414

EP - 8417

JO - JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY

JF - JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY

IS - 14

ER -