Elevated circulating AIF1L as a cell-free RNA biomarker of preeclampsia impairs trophoblast function via mitochondrial dysregulation.

Preeclampsia (PE) is a multifaceted pregnancy disorder marked by impaired trophoblast invasion and placental ischemia. Although common, dependable noninvasive biomarkers and the underlying molecular mechanisms responsible for trophoblast dysfunction are still not fully understood. In this study, we applied an integrated multi-omics strategy to uncover reliable placenta-derived circulating biomarkers and to define the functional contribution of the novel hub gene AIF1L to the pathogenesis of PE. Integrated WGCNA of placental and plasma transcriptomes identified 15 shared PE-associated genes. Among eight machine learning algorithms, the GLM model yielded optimal performance, establishing a 10-gene nomogram (including AIF1L, FLT1, and SH3PXD2A) with high diagnostic accuracy (AUC = 0.989) and robust external validation. scRNA-seq localized AIF1L expression specifically to Extravillous Trophoblasts (EVTs). Notably, both bulk and single-cell analyses revealed that AIF1L knockdown upregulates mitochondrial activity pathways. In HTR-8/SVneo cells, AIF1L silencing promoted trophoblast invasion and proliferation while inhibiting apoptosis by preserving mitochondrial membrane potential (ΔΨm) under hypoxia; conversely, AIF1L overexpression impaired mitochondrial metabolism and cell viability. We constructed a placenta-derived diagnostic nomogram for PE based on a 10-gene signature. In mechanistic assays with HTR-8/SVneo cells, our data suggest that AIF1L participates in regulating cell invasion and mitochondrial homeostasis. Our in vitro observations imply that modulating AIF1L may provide a potential research direction for exploring placental dysfunction linked to preeclampsia. We identified a robust 10-gene cfRNA signature for PE diagnosis. Our cellular experiments using HTR-8/SVneo cells indicated that upregulated AIF1L interferes with mitochondrial homeostasis and may contribute to the pathological progression of PE, suggesting its potential value as a circulating biomarker for PE screening.