title: Expression of the TRPM6 in mouse placental trophoblasts; potential role in maternal-fetal calcium transport.
abstract: The placenta is required to transport calcium (Ca2+) from mother to fetus during fetal bone mineralization. In an attempt to clarify the molecular basis of Ca2+entry for this transport, we identified TRPM6 as a candidate for apical Ca2+entry pathway. TRPM6 mRNA increased during the last 4 days of pregnancy, coinciding with fetal bone mineralization in mice. TRPM6 mRNA and protein was localized in the trophoblasts in labyrinth where the maternal-fetal Ca2+transport occurs. In patch-clamp recordings, we observed TRPM6/TRPM7-like currents in mouse trophoblasts after starting fetal bone mineralization but not before mineralization. Plasma membrane Ca2+permeability was significantly increased in TRPM6/TRPM7 expressed HEK293 cells under physiological Mg2+and ATP concentration but not in TRPM6 or TRPM7 homomer-expressing cells. These results suggest that TRPM6 is functionally expressed in mouse placental trophoblasts, implicating in maternal-fetal Ca2+transport likely with TRPM7, which might enable to sustain fetal bone mineralization.
authors.affiliation: Division of Cell Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural Sciences, Okazaki, 444-8787, Japan. yoshiro@nips.ac.jp.|Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, 444-8787, Japan. yoshiro@nips.ac.jp.
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Division of Cell Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural Sciences, Okazaki, 444-8787, Japan.|Department of Renal and Urologic Surgery, Asahikawa Medical University, Asahikawa, 078-8510, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Watanabe
authors.affiliation: Division of Cell Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural Sciences, Okazaki, 444-8787, Japan.
authors.forename: Claire T
authors.initials: CT
authors.lastname: Saito
authors.affiliation: Division of Cell Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural Sciences, Okazaki, 444-8787, Japan. tominaga@nips.ac.jp.|Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, 444-8787, Japan. tominaga@nips.ac.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Tominaga
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002463:Cell Membrane Permeability / Q000502:physiology; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D017136:Ion Transport / Q000502:physiology; D008431:Maternal-Fetal Exchange / Q000502:physiology*; D051379:Mice; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D050053:TRPM Cation Channels / Q000235:genetics / Q000378:metabolism*; D014327:Trophoblasts / Q000378:metabolism*
chemical_list: D050053:TRPM Cation Channels; C530168:Trpm6 protein, mouse; D002118:Calcium
keywords: Maternal–fetal calcium transport; Placenta; TRPM6; TRPM7; Trophoblasts