Selective silencing of placental anti-angiogenic factors in invasive trophoblasts via membrane-fusion divalent siRNA delivery for preeclampsia therapy.

Preeclampsia is a common and severe hypertensive disorder of pregnancy driven by placental dysfunction. In the absence of effective therapies, termination of pregnancy remains the only definitive treatment, resulting in significant maternal and fetal mortality. In this study, single-cell transcriptomic analysis of human placentae identified extravillous trophoblasts as a key pathogenic invasive cell subtype in preeclampsia, characterized by aberrant overexpression of fms-like tyrosine kinase-1 (Flt-1) and endoglin (Eng), the molecular sources of the soluble anti-angiogenic factors sFlt-1 and sEng. To coordinately modulate these pathogenic mediators, this study designed a novel dual-target divalent siRNA (dual-siRNA) to enhance molecular stability and enable simultaneous gene silencing, and further developed a ligand-functionalized membrane-fusogenic liposomal delivery system (iMFlip) targeting receptors highly expressed in invasive trophoblasts for selective dual-siRNA delivery. The optimized iMFlip@dual-siRNA exhibited favorable stability and low protein adsorption properties, and achieved efficient cytosolic siRNA delivery predominantly through membrane fusion, thereby substantially bypassing lysosomal degradation. In vitro, iMFlip@dual-siRNA markedly restored the invasion, migration and angiogenesis of hypoxia-injured HTR-8/SVneo cells. The subsequent pharmacodynamic studies showed that iMFlip@dual-siRNA simultaneously reduced circulating maternal sFlt-1 and sEng levels, alleviated placental vascular dysfunction and inflammatory microenvironment remodeling through reactivation of the PI3K/Akt/eNOS signaling pathway, and consequently improved maternal hypertension, proteinuria, and fetal growth restriction in a preeclamptic mouse model. Collectively, this study established a mechanism-driven therapeutic paradigm that integrated single-cell transcriptomic analysis-guided pathogenic target identification with advanced nucleic acid delivery strategies, offering a promising precision intervention approach for preeclampsia.