Key mechanisms driving extravillous trophoblast lineage imbalance in placenta accreta spectrum

Objective: This study aims to investigate the key molecular mechanisms driving EVT lineage differentiation imbalance at the maternal-fetal interface in PAS, focusing on the role of hypoxia signaling, and to explore potential therapeutic strategies.

Methods: We combined single-cell RNA sequencing and spatial transcriptomics to characterize the spatiotemporal heterogeneity of EVT subtypes in PAS and normal placentas. Hypoxia-related molecular alterations associated with EVT dysregulation were analyzed to identify key pathological regulators. Candidate regulators were functionally validated using genetically modified mouse models and trophoblast cell lines under controlled hypoxic conditions. Finally, we evaluated the therapeutic potential of modulating the EVT microenvironment by applying hypoxia-improvement strategies in both in vivo and in vitro systems.

Results: Single-cell and spatial transcriptomic analyses suggest that hypoxia signaling plays a critical regulatory role in PAS. The HIF-1 signaling pathway was significantly activated in EVT cells, with hypoxia-related genes such as HIF1A highly expressed in PAS adherent (PAS-A) samples, exhibiting distinct spatial and cellular heterogeneity. Three EVT subtypes were identified: eEVT, NOTUM? iEVT, and NOTUM? iEVT. Among them, NOTUM? iEVT was significantly enriched in PAS-A samples and associated with hypoxia response and immune modulation, whereas NOTUM? iEVT was more related to proliferation and differentiation. Additionally, imaging analysis revealed placentomegaly in PAS patients, and single-cell data showed activation of cardiac hypertrophy–related compensatory pathways in PAS nonadherent (PAS-NA) samples, suggesting structural and functional remodeling as a potential compensatory mechanism.

Conclusion: This study reveals a potential role of hypoxia signaling in EVT regulation in PAS, identifying NOTUM? iEVT as a key cell subtype in disease progression. These findings provide novel molecular insights into the pathogenesis of PAS and may inform future therapeutic targets.

Dr. Xiao Xue is professor and vice president at Sichuan University’s West China Second Hospital. She focuses on female fertility and birth defect prevention across pre-pregnancy, pregnancy, and birth stages, with work spanning reproductive microenvironment regulation, high-risk placental disorders, and clinical translation of fetal birth defect research. Dr. Xiao has published over 80 papers in leading journals, led numerous national research projects, and contributed to key clinical guidelines. She also holds multiple patents, serves on several editorial boards, and has been recognized with over 20 national and provincial awards for her contributions to maternal and child health.