Interest in the field of circular RNAs (circRNAs) is rapidly growing. Not only are circRNAs found throughout the healthy body, but they are also dysregulated in pathological states (the most researched of these being cancer). While research into the function and abundance of circRNAs has progressed, our overall understanding of these molecules remains primitive. Importantly, recent studies are elucidating new roles for circRNAs in pregnancy, particularly in the placenta. Given our knowledge that placental development shares commonalities with a “controlled cancer”, and that many of the genes responsible for circRNA production in cancer are also highly expressed in the placenta, it is likely that the same genes act in the production of circRNAs in the placenta. Furthermore, placental development shares many key signalling pathways and hallmarks with tumour growth and metastasis.
In this study we have isolated and purified circRNAs from placental tissue at multiple gestational ages classified as "term" (n=4 for 37, 38, 39, 40, 41 and 41+ weeks’ gestation). These circRNAs have been sequenced and undergone bioinformatic analyses to determine their relative expression as gestation advances. As circRNAs are known to accumulate in tissue, due to their highly robust structure making them immune to exonucleases, we determined whether circRNAs play a role in ageing of the placenta.