Previous studies show differentially expressed long non-coding RNA present in the placenta from women with pre-eclampsia, potentially playing a vital role in the pathogenesis of the complication. In a published microarray study, Ribonuclease P RNA component H1 was decreased in leukocytes from women that later developed pre-eclampsia. We hypothesized that Ribonuclease P RNA component H1 decreased during pregnancy in women developing pre-eclampsia and important for the development of the complication. We isolated RNA from extracellular vesicles, leukocytes and plasma using blood samples taken at weeks 22–24 and 36–38 in women who subsequently developed pre-eclampsia and from healthy pregnancy. The expression of Ribonuclease P RNA component H1 was quantified using qPCR. Expression of Ribonuclease P RNA component H1 at 22–24 weeks was further examined to investigate its discriminatory potential of subsequent pre-eclampsia and association with clinical markers. We found lower expression of Ribonuclease P RNA component H1 in leukocytes at 22–24 and 36–38 weeks amongst women who subsequent developed pre-eclampsia compared with those who did not, while increased Ribonuclease P RNA component H1 expression was found in plasma at 36–38 weeks. Pre-eclampsia risk factors could not account for this difference in the Ribonuclease P RNA component H1 expression. Prediction of pre-eclampsia at 22–24 weeks using Ribonuclease P RNA component H1 expression in leukocytes in addition to the screening algorithm used today had a significantly better performance. In conclusion, Ribonuclease P RNA component H1 expression in leukocytes was significantly decreased in women with pre-eclampsia, and the expression at 22–24 weeks associated with the subsequent development of pre-eclampsia. Ribonuclease P RNA component H1 in leukocytes may be a useful biomarker for prediction and/or early detection of pre-eclampsia and an unknown regulator of the signaling affecting immune cells.

Summary Sentence

The lncRNA RPPH1 was decreased in leukocytes while increased in plasma of women developing pre-eclampsia (PE). The expression level of RPPH1 was associated with markers of PE. The RPPH1 expression at 22–24 weeks predicted subsequent PE development.

Graphical Abstract