1. Iron uptake mediated by the plant-derived chelator nicotianamine in the small intestine
- Author
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Shiho Morimoto, Yoshiko Murata, Masami Yoshida, Takehiro Watanabe, Kosuke Namba, and Naho Sakamoto
- Subjects
Male ,0301 basic medicine ,5-HTP, 5-hydroxytryptophan ,Xenopus ,Phytochemicals ,Caco-2 cells ,FMOC, 9-fluorenylmethyloxycarbonyl ,Biochemistry ,Mice ,Xenopus laevis ,chemistry.chemical_compound ,DMT1, divalent metal transporter ,Intestine, Small ,Nicotianamine ,Cells, Cultured ,Chelating Agents ,Mice, Inbred ICR ,SLC36A1 ,biology ,Chemistry ,plant-derived chelator ,NA, nicotianamine ,transport metal ,Jejunum ,medicine.anatomical_structure ,transporter ,Azetidinecarboxylic Acid ,Research Article ,Duodenum ,Iron ,Biological Availability ,MAs, phytosiderophores ,Dcytb, duodenal cytochrome b ,PEPT1, oligopeptide transporter ,03 medical and health sciences ,Duodenal cytochrome B ,medicine ,Animals ,Humans ,Amino acid transporter ,oocyte ,intestine ,Molecular Biology ,TLC, thin layer chromatography ,030102 biochemistry & molecular biology ,PAT1, proton-coupled amino acid transporter ,nicotianamine ,Biological Transport ,Cell Biology ,DMT1 ,Small intestine ,Bioavailability ,FPN1, ferroportin1 ,030104 developmental biology ,Intestinal Absorption ,biology.protein ,YS1/YSL, yellow stripe 1/yellow stripe like - Abstract
Iron is an essential metal for all living organisms that is absorbed in the intestinal cells as a heme-chelated or free form. It is unclear how important plant-derived chelators, such as nicotianamine (NA), an organic small molecule that is ubiquitous in crops, vegetables, and various other foods, contribute to iron bioavailability in mammals. We performed electrophysiological assays with Xenopus laevis oocytes and radioactive tracer experiments with Caco-2 cells. The findings revealed that the proton-coupled amino acid transporter SLC36A1 (PAT1) transports iron in the form of NA-Fe (II) complex in vitro. Decreased expression of hPAT1 by RNA interference in Caco-2 cells reduced the uptake of NA-59Fe (II) complex. The uptake of inorganic 59Fe (II) was relatively unaffected. These results imply that PAT1 transports iron as a NA-Fe (II) complex. The rate of 59Fe absorption in the spleen, liver, and kidney was higher when mice were orally administered NA-59Fe (II) compared with free 59Fe (II). The profile of site-specific PAT1 expression in the mouse intestine coincided with those of NA and iron contents, which were the highest in the proximal jejunum. Orally administered NA-59Fe (II) complex in mice was detected in the proximal jejunum by thin layer chromatography. In contrast, much less 59Fe (or NA) was detected in the duodenum, where the divalent metal transporter SLC11A2 (DMT1) absorbs free Fe (II). The collective results revealed the role of PAT1 in NA-Fe (II) absorption in the intestine and potential implication of NA in iron uptake in mammals.
- Published
- 2021