Placental Growth Factor and Fms Related Tyrosine Kinase-1 are Hypomethylated in Preeclampsia Placentae

Abstract

Aim: This study aims to examine the DNA methylation (DNAm) and expression patterns of genes associated with placental angiogenesis in preeclampsia. Materials & methods: DNAm and expression were examined in normotensive (n = 100) and preeclampsia (n = 100) women using pyrosequencing and quantitative real-time PCR respectively. Results: Hypomethylation at several CpGs was observed in PlGF and FLT-1 in women with preeclampsia compared to normotensive controls. PlGF expression was lower in women with preeclampsia while FLT-1 expression was comparable. DNAm at various CpGs was negatively correlated with expression in both the genes and were associated with maternal blood pressure and birth outcomes. Conclusion: DNAm and expression of angiogenic factors in placentae are differentially regulated in preeclampsia and influence birth outcomes.

Lay abstract

Preeclampsia is a pregnancy complication affecting 8–10% of pregnant women. It has both short- and long-term effects on both the mother and baby. Altered levels of plasma angiogenic factors in early pregnancy is suggested to predict pregnancy complications such as preeclampsia. Epigenetic mechanisms such as DNA methylation may be the possible reason for the higher ratio. This study reports lower DNA methylation and gene expression patterns of PlGF and FLT-1 in placentae of women with preeclampsia as compared to control women. These changes in methylation patterns in the placentae may influence placental and fetal growth and development thereby increasing risk for cardiometabolic diseases in the children at later age. This study throws light on the possible mechanisms that influence the levels of angiogenic factors in preeclampsia.

Keywords::

• birth outcome
• DNA methylation
• FLT-1
• mRNA expression
• placenta
• PlGF
• preeclampsia

Supplementary Data

To view the supplementary data that accompany this paper please visit the journal website at: www.tandfonline.com/doi/suppl/10.2217/epi-2020-0318

Author contributions

SR Joshi, GR Chandak and DP Sundrani conceived and designed the study and interpreted the experiments. SS Mehendale helped in the recruitment of pregnant women. KM Dave was instrumental in collecting, cleaning, processing and making aliquots from the placentae. KM Dave isolated DNA and RNA and undertook expression studies from the placental samples. L Kaur performed bioinformatic analysis of the PlGF and FLT-1 genes and narrowed down the regions for DNA methylation analysis. KM Dave and L Kaur performed DNA methylation analysis. Statistical analyses were performed by KN Randhir, L Kaur and KM Dave. KM Dave wrote the first draft of the manuscript with significant inputs from L Kaur. The manuscript was finalized with inputs from DP Sundrani, GR Chandak and SR Joshi. All authors agreed to the final draft of the manuscript.

Acknowledgments

We thank all members of Mother and Child Health department, Interactive Research School for Health Affairs (IRSHA), Bharati Vidyapeeth (Deemed to be) University and Genomic Research on Complex diseases group (GRC group) labs for helpful discussions and valuable insights. Our thanks to the pregnant women and their families for participation in the study and for providing informed consent.

Financial & competing interests disclosure

This study was conducted under the aegis of Indian Council of Medical Research - Centre for Advanced Research in Preeclampsia (ICMR-CAR; Grant No. 5/7/1069/13-RCH, dt. 31/03/2017) with additional financial support from CSIR-Centre for Cellular and Molecular Biology (CSIR-CCMB). Co-author Lovejeet Kaur is currently affiliated to Translational Research Program, Translational Health Science and Technology Institute (THSTI), Faridabad. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations. In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved.

Availability of data & material

The study data are not freely available due to legal restrictions, and Government of India’s Health Ministry Screening Committee (HMSC) assessment is required to obtain the data. The anonymized data from the present study will be available on request subject to HMSC approval and Institutional Ethics committee approval.

Additional information

Funding

This study was conducted under the aegis of Indian Council of Medical Research - Centre for Advanced Research in Preeclampsia (ICMR-CAR; Grant No. 5/7/1069/13-RCH, dt. 31/03/2017) with additional financial support from CSIR-Centre for Cellular and Molecular Biology (CSIR-CCMB). Co-author Lovejeet Kaur is currently affiliated to Translational Research Program, Translational Health Science and Technology Institute (THSTI), Faridabad. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.