The piRNA PETPIR Regulates Trophoblast Function by Modulating YTHDF2-Mediated m6A Methylation of NDRG1 in Preeclampsia

Preeclampsia is marked by abnormal placental development and impaired trophoblast function. We identified Preeclampsia-associated trophoblast piRNA (PETPIR) as an important regulator of trophoblast function and m6A modifications. Placental samples from preeclamptic and healthy pregnancies were analyzed using piRNA microarrays and m6A epitranscriptomic profiling. Functional assays in trophoblast cells, transcriptomic analysis, and an in vivo PETPIR-overexpressing mouse model were employed to investigate PETPIRs mechanistic roles. We found that PETPIR was significantly upregulated in preeclamptic placentas. PETPIR inhibited trophoblast cell proliferation, migration, and invasion by inducing cell cycle arrest and apoptosis. Transcriptome analysis demonstrated that PETPIR activated hypoxia-responsive pathways. Additionally, PETPIR enhanced global m6A methylation and stabilized NDRG1 transcripts by interacting with the m6A reader YTHDF2. In vivo, PETPIR overexpression in pregnant mice recapitulated key features of preeclampsia, including maternal hypertension and fetal growth restriction. These results suggest PETPIR is a key player in the pathogenesis of preeclampsia, functioning through the PETPIR/YTHDF2/NDRG1 axis to drive hypoxia and m6A epitranscriptomic dysregulation. We provide novel insights into preeclampsias molecular mechanisms, highlighting piRNA as a promising biomarker and therapeutic target.