Goodwin Bonnie L, Corbin Karen D, Pendleton Laura C, Levy Monique M, Solomonson Larry P, Eichler Duane C
Department of Molecular Medicine, College of Medicine, University of South Florida, 12901 Bruce B. Downs Boulevard, MDC Box 7, Tampa, FL 33612-4799, USA.
Biochem Biophys Res Commun. 2008 May 30;370(2):254-8. doi: 10.1016/j.bbrc.2008.03.089. Epub 2008 Mar 28.
Vascular endothelial nitric oxide (NO) production via the citrulline-NO cycle not only involves the regulation of endothelial nitric oxide synthase (eNOS), but also regulation of caveolar-localized endothelial argininosuccinate synthase (AS), which catalyzes the rate-limiting step of the cycle. In the present study, we demonstrated that exposure of endothelial cells to troglitazone coordinately induced AS expression and NO production. Western blot analysis demonstrated an increase in AS protein expression. This increased expression was due to transcriptional upregulation of AS mRNA, as determined by quantitative real time RT-PCR and inhibition by 1-d-ribofuranosylbenzimidazole (DRB), a transcriptional inhibitor. Reporter gene assays and EMSA analyses identified a distal PPARgamma response element (PPRE) (-2471 to -2458) that mediated the troglitazone increase in AS expression. Overall, this study defines a novel molecular mechanism through which a thiazolidinedione (TZD) like troglitazone supports endothelial function via the transcriptional up-regulation of AS expression.
通过瓜氨酸-NO循环产生的血管内皮一氧化氮（NO）不仅涉及内皮型一氧化氮合酶（eNOS）的调节，还涉及小窝定位的内皮精氨琥珀酸合酶（AS）的调节，后者催化该循环的限速步骤。在本研究中，我们证明将内皮细胞暴露于曲格列酮可协同诱导AS表达和NO产生。蛋白质印迹分析表明AS蛋白表达增加。如通过定量实时RT-PCR和转录抑制剂1-d-呋喃核糖基苯并咪唑（DRB）抑制所确定的，这种表达增加是由于AS mRNA的转录上调。报告基因测定和电泳迁移率变动分析确定了一个远端PPARγ反应元件（PPRE）（-2471至-2458），其介导了曲格列酮诱导的AS表达增加。总体而言，本研究定义了一种新的分子机制，通过该机制，像曲格列酮这样的噻唑烷二酮（TZD）通过AS表达的转录上调来支持内皮功能。
