title: Action of vitamin D and the receptor, VDRa, in calcium handling in zebrafish (Danio rerio).
abstract: The purpose of the present study was to use zebrafish as a model to investigate how vitamin D and its receptors interact to control Ca(2+) uptake function. Low-Ca(2+) fresh water stimulated Ca(2+) influx and expressions of epithelial calcium channel (ecac), vitamin D-25-hydroxylase (cyp2r1), vitamin D receptor a (vdra), and vdrb in zebrafish. Exogenous vitamin D increased Ca(2+) influx and expressions of ecac and 25-hydroxyvitamin D(3)-24-hydroxylase (cyp24a1), but downregulated 1α-OHase (cyp27b1) with no effects on other Ca(2+) transporters. Morpholino oligonucleotide knockdown of VDRa, but not VDRb, was found as a consequence of calcium uptake inhibition by knockdown of ecac, and ossification of vertebrae is impaired. Taken together, vitamin D-VDRa signaling may stimulate Ca(2+) uptake by upregulating ECaC in zebrafish, thereby clarifying the Ca(2+)-handling function of only a VDR in teleosts. Zebrafish may be useful as a model to explore the function of vitamin D-VDR signaling in Ca(2+) homeostasis and the related physiological processes in vertebrates.
authors.affiliation: Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan, ROC.
authors.forename: Chia-Hao
authors.initials: CH
authors.lastname: Lin
authors.forename: Che-Hsien
authors.initials: CH
authors.lastname: Su
authors.forename: Deng-Yu
authors.initials: DY
authors.lastname: Tseng
authors.forename: Feng-Chun
authors.initials: FC
authors.lastname: Ding
authors.forename: Pung-Pung
authors.initials: PP
authors.lastname: Hwang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism*; D017931:DNA Primers; D055785:Gene Knockdown Techniques; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D018167:Receptors, Calcitriol / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D050916:TRPV Cation Channels / Q000235:genetics / Q000502:physiology; D014807:Vitamin D / Q000235:genetics / Q000502:physiology*; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics / Q000502:physiology
chemical_list: D017931:DNA Primers; D012333:RNA, Messenger; D018167:Receptors, Calcitriol; D050916:TRPV Cation Channels; D029961:Zebrafish Proteins; C505134:trpv6 protein, zebrafish; D014807:Vitamin D; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium