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Logo of arthrestherBioMed Centralbiomed central web sitesearchsubmit a manuscriptregisterthis articleArthritis Research & Therapy
 
Arthritis Res Ther. 2006; 8(2): R36.
Published online Jan 16, 2006. doi:  10.1186/ar1890
PMCID: PMC1526589
The induction of CCN2 by TGFβ1 involves Ets-1
Jonathan P Van Beek,1 Laura Kennedy,1 Jason S Rockel,1 Suzanne M Bernier,1 and Andrew Leaskcorresponding author1
1CIHR Group in Skeletal Development and Remodeling, Schulich School of Medicine and Dentistry, Dental Sciences Building, The University of Western Ontario, London, ON N6A 5C1, Canada
corresponding authorCorresponding author.
Jonathan P Van Beek: jvb/at/wwo.ca; Laura Kennedy: lk/at/uwo.ca; Jason S Rockel: jr/at/uwo.ca; Suzanne M Bernier: sb/at/uwo.ca; Andrew Leask: Andrew.Leask/at/schulich.uwo.ca
Received October 15, 2005; Revisions requested December 15, 2005; Revised December 19, 2005; Accepted December 19, 2005.
Abstract
CCN2 is encoded by an immediate-early gene induced in mesenchymal cells during the formation of blood vessels, bone and connective tissue. It plays key roles in cell adhesion and migration, as well as matrix remodeling. CCN2 is overexpressed in fibrosis, arthritis and cancer; thus, an understanding of how to control CCN2 expression is likely to have importance in developing therapies to combat these pathologies. Previously, we found that the promoter sequence GAGGAATG is important for Ccn2 gene regulation in NIH 3T3 fibroblasts. In this report, we show that this sequence mediates activation of the CCN2 promoter by the ETS family of transcription factors. Endogenous Ets-1 binds this element of the CCN2 promoter, and dominant negative Ets-1 and specific Ets-1 small interfering RNA block induction of CCN2 expression by TGFβ. In the absence of added TGFβ1, Ets-1, but not the related fli-1, synergizes with Smad 3 to activate the CCN2 promoter. Whereas the ability of transfected Ets-1 to activate the CCN2 promoter is dependent on protein kinase C (PKC), Ets-1 in the presence of co-transfected Smad3 does not require PKC, suggesting that the presence of Smad3 bypasses the requirement of Ets-1 for PKC to activate target promoter activity. Our results are consistent with the notion that Smad3 and Ets-1 cooperate in the induction of the CCN2 promoter by TGFβ1. Antagonizing Ets-1 might be of benefit in attenuating CCN2 expression in fibrosis, arthritis and cancer, and may be useful in modulating the outcome of these disorders.
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