PIWI-interacting RNA sequencing profiles in maternal plasma-derived exosomes reveal novel non-invasive prenatal biomarkers for the early diagnosis of nonsyndromic cleft lip and palate.

Background: Congenital malformations are common birth defects with high neonatal morbidity and mortality. It is essential to find simpler and more efficient biomarkers for early prenatal diagnosis. Therefore, we investigated PIWI-interacting RNAs (piRNAs) as potential prenatal biomarkers in plasma-derived exosomes from pregnant women carrying foetuses with congenital malformations.

Methods: Small RNA sequencing was used to screen piRNA biomarkers in plasma-derived exosomes of five pregnant women carrying foetuses with nonsyndromic cleft lip and palate (nsCLP) and five women carrying normal foetuses. Differentially expressed piRNAs were verified in 270 pregnant women, including 111 paired women carrying foetuses with congenital malformations and normal foetuses (at 24 gestational weeks), 10 paired women carrying foetuses with nsCLP and normal foetuses (at 15-19 gestational weeks), and 28 women at different stages of normal pregnancy. piRNA biomarkers were also verified in placentas, umbilical cords, fetal medial calf muscles, and lip tissues of nsCLP and normal foetuses.

Findings: We identified a biomarker panel of three pregnancy-associated exosomal piRNAs (hsa-piR-009228, hsa-piR-016659, and hsa-piR-020496) could distinguish nsCLP foetuses from normal foetuses. These three piRNAs had better diagnostic accuracy for nsCLP at the early gestational stage, at which time typical malformations were not detected upon prenatal ultrasound screening, and had diagnostic value for neural tube defects (NTDs) and congenital heart defects (CHDs).

Interpretation: Our work revealed the potential clinical applications of piRNAs for predicting nsCLP, NTDs, and CHDs.

Funding: National Key Research and Development Program, National Natural Science Foundation of China, and LiaoNing Revitalization Talents Program .