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Mammary Epithelial Cells Modulate TRPM6 Expression in Response to Variations of Magnesium Availability
Author(s) -
Wolf Federica I,
Trapani Valentina,
Mastrototaro Lucia,
Cittadini Achille
Publication year - 2010
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.24.1_supplement.1027.1
Subject(s) - magnesium , chemistry , hypomagnesemia , extracellular , transcellular , cell culture , medicine , endocrinology , microbiology and biotechnology , biophysics , biochemistry , biology , organic chemistry , genetics
Mammary epithelial cells (HC11) chronically adapted to grow in a low‐magnesium (0.05 mM vs. 0.5 mM) or in a high‐magnesium (40 mM) medium were used to investigate on the mechanisms of cell magnesium transport under conditions of non‐physiological magnesium availability. Magnesium influx was higher in low‐magnesium cells compared to control or high‐magnesium cells, this influx was abolished by Co(III)hexaammine, an inhibitor of magnesium channels. Among the Mg‐transporting channels recently characterized, e.g. MagT1, SLC41A1, transient receptor potential meastatin (TRPM7) was shown to mediate magnesium uptake ubiquitously at cell/tissue level, whereas TRPM6 seems to be responsible for transcellular magnesium absorption or re‐absorption in the intestine and kidney, respectively. We found that HC11 cells grown in low magnesium upregulated mRNA for TRPM6 and not for TRPM7 or MagT1. Consistent with these results, TRPM6 protein level as assessed by western blot, was inversely related to extracellular magnesium, namely low‐magnesium cells > control cells > high‐magnesium cells and was also rapidly up‐ or down‐modulated in HC11 cells acutely deprived of magnesium or in low‐magnesium cells re‐added with magnesium, respectively. These results suggest, for the first time, that TRPM6 contributes to regulating magnesium influx in mammary epithelial cells. Supported by the Italian MIUR‐PRIN 2007ZT39FN.