title: Functional interaction of osteogenic transcription factors Runx2 and Vdr in transcriptional regulation of Opn during soft tissue calcification.
abstract: Loss of Abcc6 gene expression was identified to be responsible for dystrophic calcification of the heart (DCC) or vessels after acute injury in several strains of laboratory mice. This calcification shares features with osteogenesis and may involve osteogenic factors. Tissue expression of osteopontin (Opn) and 11 osteogenic transcription factors were studied in vivo in mouse models for DCC and in vitro using luciferase reporter gene assays. Compared with DCC-resistant C57BL/6 mice, a significant increase in Opn transcription was demonstrated in necrotic lesions of both DCC-susceptible C3H/He and B6.C3H(Dyscalc1) congenic mice at day 3 after injury. Significant increases in gene expression were also demonstrated for the transcription factors runt domain-containing transcription factor 2 (Runx2), vitamin D receptor (Vdr), SRY (sex-determining region Y)-box 9 protein, and Nfkb1 in C3H/He mice versus C57BL/6 controls. However, only Runx2 remained significantly increased in the B6.C3H(Dyscalc1) congenic mice, which carry only the Dyscalc1 locus with functional Abcc6 deletion on a C57BL/6 genetic background. Luciferase assay use increased Opn promoter activity, which was demonstrated after overexpression of Runx2. A poly-T stretch insertion was identified to stabilize the binding of Runx2, thus significantly enhancing Opn promoter activity. This Runx2-mediated activation was further enhanced by cotransfection with Vdr. Our data suggest a key role of Runx2 in the regulation of Opn in a model of cardiovascular calcification and demonstrate a synergistic cooperation of Runx2 and Vdr.
authors: Institute for Integrative and Experimental Genomics and DZHK-German Centre for Cardiovascular Research, partner site Lübeck/Hamburg/Kiel, University of Lübeck, Lübeck, Germany.
authors: Ann-Kathrin
authors: AK
authors: Sowa
authors: Frank J
authors: FJ
authors: Kaiser
authors: Juliane
authors: J
authors: Eckhold
authors: Thorsten
authors: T
authors: Kessler
authors: Redouane
authors: R
authors: Aherrahrou
authors: Sandra
authors: S
authors: Wrobel
authors: Piotr M
authors: PM
authors: Kaczmarek
authors: Lars
authors: L
authors: Doehring
authors: Heribert
authors: H
authors: Schunkert
authors: Jeanette
authors: J
authors: Erdmann
authors: Zouhair
authors: Z
authors: Aherrahrou
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000172:deficiency; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism*; D005260:Female; D007150:Immunohistochemistry; D008163:Luminescent Measurements; D051379:Mice; D008810:Mice, Inbred C57BL; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D053495:Osteopontin / Q000378:metabolism*; D018167:Receptors, Calcitriol / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D061205:Vascular Calcification / Q000378:metabolism*
chemical_list: D018528:ATP-Binding Cassette Transporters; D015415:Biomarkers; D050659:Core Binding Factor Alpha 1 Subunit; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D053495:Osteopontin; D018167:Receptors, Calcitriol; C504743:Abcc6 protein, mouse; C493716:Runx2 protein, mouse; C506896:Spp1 protein, mouse