title: The classic receptor for 1alpha,25-dihydroxy vitamin D3 is required for non-genomic actions of 1alpha,25-dihydroxy vitamin D3 in osteosarcoma cells.
abstract: 1alpha,25-dihydroxy vitamin D3 has a major role in the regulation of the bone metabolism as it promotes the expression of key bone-related proteins in osteoblastic cells. In recent years it has become increasingly evident that in addition to its well-established genomic actions, 1alpha,25-dihydroxy vitamin D3 induces non-genomic responses by acting through a specific plasma membrane-associated receptor. Results from several groups suggest that the classical nuclear 1alpha,25-dihydroxy vitamin D3 receptor (VDR) is also responsible for these non-genomic actions of 1alpha,25-dihydroxy vitamin D3. Here, we have used siRNA to suppress the expression of VDR in osteoblastic cells and assessed the role of VDR in the non-genomic response to 1alpha,25-dihydroxy vitamin D3. We report that expression of the classic VDR in osteoblasts is required to generate a rapid 1alpha,25-dihydroxy vitamin D3-mediated increase in the intracellular Ca(2+) concentration, a hallmark of the non-genomic actions of 1alpha,25-dihydroxy vitamin D3 in these cells.
authors.affiliation: Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias Biologicas, Universidad de Concepcion, Concepcion, Chile.
authors.forename: Soraya
authors.initials: S
authors.lastname: Bravo
authors.forename: Roberto
authors.initials: R
authors.lastname: Paredes
authors.forename: Pamela
authors.initials: P
authors.lastname: Izaurieta
authors.forename: Jane B
authors.initials: JB
authors.lastname: Lian
authors.forename: Janet L
authors.initials: JL
authors.lastname: Stein
authors.forename: Gary S
authors.initials: GS
authors.lastname: Stein
authors.forename: Maria Victoria
authors.initials: MV
authors.lastname: Hinrichs
authors.forename: Juan
authors.initials: J
authors.lastname: Olate
authors.forename: Luis G
authors.initials: LG
authors.lastname: Aguayo
authors.forename: Martin
authors.initials: M
authors.lastname: Montecino
mesh_terms: D000818:Animals; D016678:Genome / Q000235:genetics*; D012516:Osteosarcoma / Q000473:pathology*; D034741:RNA, Small Interfering; D051381:Rats; D018167:Receptors, Calcitriol / Q000378:metabolism*; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D034741:RNA, Small Interfering; D018167:Receptors, Calcitriol; C118756:dihydroxy-vitamin D3; D014807:Vitamin D