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Hepcidin attenuates zinc efflux in Caco‐2 cells
Author(s) -
Hennigar Stephen R.,
McClung James P.
Publication year - 2016
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.30.1_supplement.292.3
Subject(s) - hepcidin , metallothionein , chemistry , western blot , zinc , caco 2 , endocrinology , medicine , intracellular , microbiology and biotechnology , inflammation , biochemistry , cell , biology , gene , organic chemistry
Hepcidin, a peptide hormone produced by theliver in response to iron loading and inflammation, regulates body iron storesby inhibiting iron transporter function. Zinc also regulates hepcidinexpression; however, the effects of hepcidin on zinc transport and zinctransporter function have not been documented. The objective of this study wasto determine whether hepcidin affects intestinal zinc transport. Differentiatedhuman intestinal Caco‐2 cells were treated ± 1μM hepcidin for 3–24 h. Zinctransport was assessed in cells seeded on Transwell inserts. Media was collected from the apical and basolateral chambers and 67 Znconcentrations were determined by ICP‐MS. Expression of metallothionein ( MT1A ), ZIP4 ( SLC39A4 ), and ZnT1 ( SLC30A1 )was determined using RT‐qPCR and Western blot. Hepcidin attenuated zinctransport, as cells treated with hepcidin exported 20 and 26% less 67 Zninto the basolateral chamber at 3 h and 24 h ( P <0.05), respectively, and retained more cellular 67 Zn( P <0.05) as compared to control cells. Intracellular zinc in control cells was localized to vesicles dispersed throughout the cytoplasm; however, the number of vesicles and intensity of FluoZin‐3 fluorescence decreased ( P <0.05)in cells treated with hepcidin for 24 h. The mRNA abundance of metallothionein increased 1.5‐fold ( P <0.05). ZIP4 protein remained unchanged ( P >0.05), whereas hepcidin reduced ZnT1 protein by 75% ( P <0.05) as compared to control cells. These data suggest that hepcidin is a regulatory hormone that manages zinc transport in intestinal cells by downregulating ZnT1 to reduce zinc export and increasing metallothionein to buffer the rise in intracellular zinc. Understanding the mechanism and role of hepcidin in zinc homeostasis may provide insight into the hypozincemiaassociated with inflammation and infection. Support or Funding Information Support provided by USAMRMC.