title: Down-regulation by nuclear factor kappaB of human 25-hydroxyvitamin D3 1alpha-hydroxylase promoter.
abstract: 1,25-(OH)(2) vitamin D(3) is important for calcium homeostasis and cell differentiation. The key enzyme for the activation of liver-derived 25(OH) vitamin D(3) is 25-hydroxyvitamin D(3) 1alpha-hydroxylase. It is expressed mainly in the kidney but also in peripheral tissues. A 1413-bp fragment of the 1alpha-hydroxylase promoter was cloned into luciferase vectors pGL2basic and pGL3basic. Sequence analyses revealed four base exchanges and three base deletions compared with the published sequence which were identically found in five control persons. In silico promoter analyses revealed 17 putative nuclear factor (NF)kappaB sites, 10 of which were found to bind NFkappaB in EMSA experiments. Cotransfection of NFkappaB p50 and p65 subunits resulted in dramatic reduction of the promoter activity of the full-length construct as well as a series of 5'-deletion constructs. Deletion of the farmost 3'-situated NFkappaB-responsive element almost abolished NFkappaB responsiveness. Treatment of human embryonic kidney 293 cells with sulfasalazine, a NFkappaB inhibitor, resulted in enhanced 1alpha-hydroxylase mRNA production. Down-regulation of 1alpha-hydroxylase promoter through NFkappaB signaling may contribute to the pathogenesis of inflammation-associated osteopenia/osteoporosis.
authors.affiliation: Orthopedic Department, University of Wuerzburg, Wuerzburg, Germany.
authors.forename: Regina
authors.initials: R
authors.lastname: Ebert
authors.forename: Marlena
authors.initials: M
authors.lastname: Jovanovic
authors.forename: Matthias
authors.initials: M
authors.lastname: Ulmer
authors.forename: Doris
authors.initials: D
authors.lastname: Schneider
authors.forename: Jutta
authors.initials: J
authors.lastname: Meissner-Weigl
authors.forename: Jerzy
authors.initials: J
authors.lastname: Adamski
authors.forename: Franz
authors.initials: F
authors.lastname: Jakob
mesh_terms: D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000235:genetics*; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D017931:DNA Primers; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics*; D006801:Humans; D007249:Inflammation / Q000235:genetics; D016297:Mutagenesis, Site-Directed; D016328:NF-kappa B / Q000502:physiology*; D010024:Osteoporosis / Q000235:genetics; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000378:metabolism; D017384:Sequence Deletion; D014162:Transfection
chemical_list: D017931:DNA Primers; D016328:NF-kappa B; D011994:Recombinant Proteins; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase