Placental Defects: An Epigenetic Perspective

Placenta, the first organ to be formed during gestation, plays a crucial role in intrauterine regulation of fetal growth and is involved in several functions during fetal development such as exchange of nutrients, wastes, and gases; protection against maternal immune rejection; and various metabolic and endocrine functions. Several studies have shown the regulation of epigenetic factors and the phenomenon of genomic imprinting in placentation and embryogenesis. Any gain or loss of imprint marks in the placenta has been shown to associate with severe placental defects which in turn affect both the mother and the growing fetus and can have long-term effects during adulthood. Using candidate and genome-wide high throughput approaches, several studies have shown association between aberrant epigenetic factors in the form of DNA methylation, histone modifications, and non-coding RNAs and placental defects in both human and animal models as well as using in vitro studies. In the current review, we discuss several placenta-related pathophysiologies and their association with various aberrant epigenetic factors and gene expression patterns in both in vivo and in vitro systems. This review will help the researchers gain insight into the recent evidences in the area of placentation and epigenetics and to design novel strategies to study and prevent the defects in this underestimated organ.