Molecular Sciences - Posters B
Orsolya Oravecz1,2 , Máté Posta1,3, Roberto Romero4,5 ,Yi Xu4,5, Kata Juhász1, Andrea Balogh1, Zhonghui Xu4, Zsolt Gelencsér1, Gábor Szalai1, Petronella Hupuczi6, Padma Murthi7,8, Martin Knöfler9, Offer Erez4,5,10, Adi L. Tarca4,5, Nándor Ács11, Zoltán Papp6,11, Nándor Gábor Than1,6,11
1Systems Biology of Reproduction Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary;
2Doctoral School of Biology, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary;
3Károly Rácz Doctoral School of Clinical Medicine, Semmelweis University, Budapest, Hungary;
4 Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, United States Department of Health and Human Services, Detroit, MI, United States;
5Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI, United States;
6Maternity Private Clinic of Obstetrics and Gynecology, Budapest, Hungary;
7Department of Pharmacology, Monash Biomedicine Discovery Institute, Clayton, Australia;
8Department of Obstetrics and Gynaecology, University of Melbourne, Royal Women's Hospital, Parkville, Australia;
9Placental Development Group, Department of Obstetrics and Gynaecology, Reproductive Biology Unit, Medical University of Vienna, Vienna, Austria.
10Department of Obstetrics and Gynecology, Soroka University Medical Center, Beer Sheva, Israel;
11Department of Obstetrics and Gynecology, Semmelweis University, Budapest, Hungary;
Introduction: The placenta comprises highly specialized trophoblast cell types, including syncytiotrophoblast and extravillous trophoblast. Their formation and specialization are all governed by transcription factors. One of the largest transcription factor families in the human genome, zinc-finger proteins (ZNFs), plays a vital role in placental development and trophoblast differentiation. ZNF554 was earlier found to be highly expressed in the placenta, where it regulates trophoblastic functions including deep invasion into maternal tissues, a feature uniquely present in humans and inhibited in preeclampsia.
Aim: We investigated how the evolution of the ZNF554 locus affected the regulation of placental ZNF554 expression, trophoblast invasion, and the vulnerability to preeclampsia.
Methods: The evolution of the ZNF554 locus was examined in silico using the USCS Genome Brower. The transcriptional regulation of ZNF554 by ZEB1, ZEB2, and hypoxia was investigated in vitro by luciferase assay. We investigated the neighboring hypoxia-response elements (HREs) located in AluY and their hypermethylation in preeclampsia. For this, we analyzed three CpG deletion clones by luciferase assay.
Results: In primates, the ZNF554 locus evolved through the insertion of primate-specific transposable elements, leading to the establishment of ZEB binding sites and HREs in the 5' flanking region. In humans, the LTR10A elements were multiplicated, which introduced numerous ZEB binding sites into the promoter region. Co-transfection with ZEB1/2 increased reporter activity in extravillous trophoblasts, influenced by oxygen concentration. Deletion of CpG in HREs in AluY decreased reporter activity, suggesting that epigenetic mechanisms regulate decreased ZNF554 expression in preterm preeclampsia.
Conclusion: The study revealed that evolutionary changes in the ZNF554 locus enabled the regulation of ZNF554 expression by hypoxia and ZEB transcription factors in extravillous trophoblasts, facilitating deep trophoblast invasion in humans. Our data suggest that ZNF554 downregulation by epigenetic mechanisms is involved in preeclampsia pathology.
Funding: This research was supported by the Hungarian Academy of Sciences Momentum “LP2014-7/2014 (T. N. G.) and Premium_2019-436 (B. A.) grants; the Hungarian National Research, Development and Innovation Fund grant “FIEK_16-1-2016-0005”.