The von Hippel Lindau tumour suppressor gene is a novel target of E2F4-mediated transcriptional repression in preeclampsia

BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE

卷:1864

Article

Alahari, Sruthi^1,2  Garcia, Julia¹  Post, Martin^2,4  Caniggia, Isabella^1,2,3 

[1] Mt Sinai Hosp, Lunenfeld Tanenbaum Res Inst, 25 Orde St,Room 6-1004-3, Toronto, ON M5T 3H7, Canada

[2] Univ Toronto, Dept Physiol, Toronto, ON M5S 1A8, Canada

[3] Univ Toronto, Dept Obstet & Gynecol, Toronto, ON M5G 1E2, Canada

[4] Hosp Sick Children, Translat Med Program, Peter Gilgan Ctr Res & Learning, 686 Bay St, Toronto, ON M5G 1X8, Canada

关键词: VHL;    DNA methylation;    E2F4;    Placenta;    Preeclampsia;    Transforming growth factor Beta;   

DOI  :  10.1016/j.bbadis.2018.07.016

来源: Elsevier

【 摘 要 】

The von Hippel Lindau tumour suppressor (VHL) protein is essential for proper placental development and is downregulated in preeclampsia (PE), a devastating disorder of pregnancy typified by chronic hypoxia. To date, knowledge on VHL genetic and epigenetic regulation is restricted to inactivating mutations and loss-of-heterozygosity in renal cell carcinomas. Herein, we sought to examine whether VHL DNA is subject to differential methylation, and if so, whether it is altered in early-onset PE (E-PE). Sodium bisulfite modification and methylation-specific PCR analysis revealed that VHL is subject to extensive methylation in a CpG-rich region within its promoter in the human placenta. Notably, we detected significant differences in methylation in E-PE placentae relative to normotensive age-matched controls at key transcription factor binding sites, including that of the transcriptional repressor E2F4. Treatment of JEG3 cells with 5-Aza-2'-deoxycytidine, revealed that loss of DNA methylation promoted VHL transcription by attenuating VHL association with E2F4. RNAi knockdown of E2F4 in vitro confirmed its function on VHL repression. Exposure of JEG3 cells to transforming growth factor beta (TGF beta) downregulated VHL mRNA. In line with elevated levels of TGF beta 3 in E-PE, chromatin immunoprecipitation assays revealed that E2F4-VHL association was enhanced upon TGF beta 3 treatment, indicative of VHL transcriptional inhibition. In line with decreased VHL expression in E-PE, augmented E2F4-VHL association was also observed in E-PE placental tissue relative to controls. In conclusion, we demonstrate for the first time that hypomethylation of VHL DNA at a key transcription factor binding site has significant consequences for its transcriptional repression in early-onset preeclampsia.

【 授权许可】

Free