title: Stanniocalcin-1 controls ion regulation functions of ion-transporting epithelium other than calcium balance.
abstract: Stanniocalcin-1 (STC-1) was first identified to involve in Ca(2+) homeostasis in teleosts, and was thought to act as a hypocalcemic hormone in vertebrate. Recent studies suggested that STC-1 exhibits broad effects on ion balance, not confines to Ca(2+), but the mechanism of this regulation process remains largely unknown. Here, we used zebrafish embryos as an alternative in vivo model to investigate how STC-1 regulates transepithelial ion transport function in ion-transporting epithelium. Expression of stc-1 mRNA in zebrafish embryos was increased in high-Ca(2+) environments but decreased by acidic and ion-deficient treatments while overexpression of stc-1 impaired the hypotonic acclimation by decreasing whole body Ca(2+), Na(+), and Cl(-) contents and H(+) secretion ability. Injection of STC-1 mRNA also down-regulated mRNA expressions of epithelial Ca(2+) channel, H(+)-ATPase, and Na(+)-Cl(-) cotransporter, suggesting the roles of STC-1 in regulation of ions other than Ca(2+). Knockdown of STC-1 caused an increase in ionocyte progenitors (foxi3a as the marker) and mature ionocytes (ion transporters as the markers), but did not affect epithelium stem cells (p63 as the marker) in the embryonic skin. Overexpression of STC-1 had the corresponding opposite effect on ionocyte progenitors, mature ionocytes in the embryonic skin. Taken together, STC-1 negatively regulates the number of ionocytes to reduce ionocyte functions. This process is important for body fluid ionic homeostasis, which is achieved by the regulation of ion transport functions in ionocytes. The present findings provide new insights into the broader functions of STC-1, a hypocalcemic hormone.
authors.affiliation: 1. Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan. ; 2. RIKEN Brain Science Institute, Laboratory for Developmental Gene Regulation, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
authors.forename: Ming-Yi
authors.initials: MY
authors.lastname: Chou
authors.affiliation: 1. Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Chia-Hao
authors.initials: CH
authors.lastname: Lin
authors.affiliation: 1. Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Pei-Lin
authors.initials: PL
authors.lastname: Chao
authors.affiliation: 1. Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Jo-Chi
authors.initials: JC
authors.lastname: Hung
authors.affiliation: 1. Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Shelly A
authors.initials: SA
authors.lastname: Cruz
authors.affiliation: 1. Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Pung-Pung
authors.initials: PP
authors.lastname: Hwang
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation; D002712:Chlorides / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000378:metabolism; D004848:Epithelium / Q000187:drug effects* / Q000378:metabolism*; D006023:Glycoproteins / Q000494:pharmacology*; D017136:Ion Transport / Q000502:physiology; D012964:Sodium / Q000378:metabolism; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D002712:Chlorides; D006023:Glycoproteins; D029961:Zebrafish Proteins; C051795:teleocalcin; D012964:Sodium; D002118:Calcium
keywords: differentiation; ion regulation; ionocyte; stanniocalcin; zebrafish.