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Mechanism of Copper Absorption Investigated in Caco2 and HuTu80 Enterocyte Models
Author(s) -
Ricarte Adrian,
Valadez Angelica,
Arabpour Auriana,
Kidane Theodros,
Linder Maria
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.1011.3
Subject(s) - dmt1 , enterocyte , ferrous , chemistry , absorption (acoustics) , caco 2 , copper , transporter , sodium , chloride , cell , biophysics , biochemistry , microbiology and biotechnology , biology , gene , small intestine , materials science , organic chemistry , composite material
How dietary copper is absorbed by enterocytes in the small intestine is still not well understood, and certain aspects continue to be controversial. To shed further light on this process, we used two different human enterocyte models, first determining the expression of mRNA for genes that might be involved. As determined by qPCR, both Caco2 and HuTu cells expressed CTR1, DMT1, and Steap 3, but not Steap 4. Caco2 cells also expressed some Steap 2, but not dCytB; HuTu cells expressed some dCytB. CTR1 expression (relative to 18S RNA) was 2.5x greater in Caco2 cells, whereas that of DMT1 was 2x greater in HuTu80 cells. Rates of Cu uptake were determined with 5 uM 64 Cu‐labeled Cu(I)‐histidine and cell monolayers with tight junctions growing in bicameral chambers. Uptake across the apical membrane of both cell lines was inhibited about 50% by 50 uM Ag(I). Interestingly, substitution of sodium sulfate for sodium chloride in the uptake solution had little or no effect, implying no chloride dependence. In iron‐deficient HuTu cells, uptake of 5 uM 59 Fe(II) was inhibited ~50% by a combination of drugs targeting DMT1. However, the same drug combination and conditions enhanced rather than inhibited 64 Cu uptake. These initial findings continue to support the concept that CTR1 is important for copper absorption. They also imply that neither DMT1 nor a chloride‐dependent channel play a significant role.