Suppression of rat thromboxane synthase gene transcription by peroxisome proliferator-activated receptor gamma in macrophages via an interaction with NRF2.

Abstract

We have studied the transcription regulation of the rat thromboxane synthase (TXS) gene by peroxisome proliferator-activated receptor gamma (PPARgamma) in macrophages. The transcription activity of a cloned 5'-flanking region (1.6 kilobases) of the rat TXS gene (5'FL-TXS) was examined by luciferase reporter gene assay. TXS mRNA expression and the transcription activity of 5'FL-TXS were inhibited by PPARgamma ligands, 15-deoxy-Delta(12,14)-prostaglandin J(2) (PGJ(2)), and the thiazolidinedione troglitazone (TRO) in a dose-dependent manner. Overexpression of PPARgamma also significantly suppressed transcription, and further addition of PGJ(2) or TRO augmented the suppression. Deletion analysis showed that the element responsible for the PPARgamma effect is located in a region containing the nuclear factor E2 (NF-E2)/AP-1 site (-98/-88), which was indicated to be the major promoter of the TXS gene. By electrophoretic mobility shift assay using the NF-E2/AP-1 site and nuclear extracts from macrophages, we observed a specific protein-DNA complex formation, which was inhibited by a specific antibody against the transcription factor NRF2 (NF-E2-related factor 2). Moreover, the complex was decreased with PGJ(2), TRO, or in vitro translated PPARgamma. The transcription suppression by PPARgamma was confirmed using this truncated NRF2-binding element (-98/-88) by the reporter gene assay. Finally, a direct interaction between PPARgamma and NRF2 was confirmed by glutathione S-transferase pull-down assay. In conclusion, the NRF2-binding site (-98/-88) is the major promoter of 5'FL-TXS which can be suppressed by activated PPARgamma via a protein-protein interaction with NRF2 in macrophages.

0100200'02'04'06'08'10'12'14'16
Citations per Year

841 Citations

Semantic Scholar estimates that this publication has 841 citations based on the available data.

See our FAQ for additional information.

Cite this paper

@article{Ikeda2000SuppressionOR, title={Suppression of rat thromboxane synthase gene transcription by peroxisome proliferator-activated receptor gamma in macrophages via an interaction with NRF2.}, author={Y. Ikeda and Akira Sugawara and Yoshihiro Taniyama and Akira Uruno and Kazuei Igarashi and Shuji Arima and Satoru Ito and Koji Takeuchi}, journal={The Journal of biological chemistry}, year={2000}, volume={275 42}, pages={33142-50} }