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Osteopontin transcription in aortic vascular smooth muscle cells is controlled by glucose-regulated upstream stimulatory factor and activator protein-1 activities.

Authors: Bidder, M  Shao, JS  Charlton-Kachigian, N  Loewy, AP  Semenkovich, CF  Towler, DA 
Citation: Bidder M, etal., J Biol Chem 2002 Nov 15;277(46):44485-96.
Pubmed: (View Article at PubMed) PMID:12200434
DOI: Full-text: DOI:10.1074/jbc.M206235200

The expression of the matrix cytokine osteopontin (OPN) is up-regulated in aortic vascular smooth muscle cells (VSMCs) by diabetes. OPN expression in cultured VSMCs is reciprocally regulated by glucose and 2-deoxyglucose (2-DG; inhibitor of cellular glucose metabolism). Systematic analyses of OPN promoter-luciferase reporter constructs identify a CCTCATGAC motif at nucleotides -80 to -72 relative to the initiation site that supports OPN transcription in VSMCs. The region -83 to -45 encompassing this motif confers basal and glucose- and 2-DG-dependent transcription on an unresponsive promoter. Competition and gel mobility supershift assays identify upstream stimulatory factor (USF; USF1:USF2) and activator protein-1 (AP1; c-Fos:c-Jun) in complexes binding the composite CCTCATGAC element. Glucose up-regulates both AP1 and USF binding activities 2-fold in A7r5 cells and selectively up-regulates USF1 protein levels. By contrast, USF (but not AP1) binding activity is suppressed by 2-DG and restored by glucose treatment. Expression of either USF or AP1 activates the proximal OPN promoter in A7r5 VSMCs in part via the CCTCATGAC element. Moreover, glucose stimulates the transactivation functions of c-Fos and USF1, but not c-Jun, in one-hybrid assays. Mannitol does not regulate binding, transactivation functions, USF1 protein accumulation, or OPN transcription. Thus, OPN gene transcription is regulated by USF and AP1 in aortic VSMCs, entrained to changes in cellular glucose metabolism.


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RGD Object Information
RGD ID: 634232
Created: 2003-08-29
Species: All species
Last Modified: 2004-05-25
Status: ACTIVE


RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.