Mechanistic Insights into LINC00923 in Preeclampsia Placental Exosomes Regulating Trophoblast Function via the miR-203a-3p- CACNG7 Axis

Background : Preeclampsia (PE) is a pregnancy-specific hypertensive disorder characterized by new-onset hypertension after 20 weeks of gestation accompanied by proteinuria or other systemic manifestations, with a global incidence of 2-8%. As a major obstetric complication, PE significantly contributes to maternal and perinatal mortality. The core pathological mechanism involves insufficient trophoblast invasion leading to impaired spiral artery remodeling, ultimately resulting in placental ischemia and systemic vascular endothelial dysfunction. Recent studies have demonstrated that placental-derived exosomes serve as crucial mediators of maternal-fetal communication by delivering non-coding RNAs to regulate trophoblast function. However, the molecular regulatory networks and clinical translational potential of exosomal non-coding RNAs in PE remain poorly understood. Although long non-coding RNA LINC00923 has been implicated in tumorigenesis, its role in PE through exosome-mediated trophoblast regulation remains unclear. Additionally, the involvement of miR-203a-3p and calcium channel gene CACNG7 in PE has not been reported. Objective: This study aims to elucidate the mechanism by which PE placental exosomes regulate trophoblast function through the LINC00923/miR-203a-3p/CACNG7 axis, providing new insights into PE pathogenesis and potential therapeutic targets. Methods: 1.Sample collection and exosome isolation: Placental tissues were collected from 3 PE patients and 3 healthy controls. Exosomes were isolated using differential centrifugation combined with ultrafiltration and characterized by transmission electron microscopy, nanoparticle tracking analysis, and Western blot (CD9+/CD81+/TSG101+). 2.Functional assays: The effects of exosomes (50 μg/mL, 48h) on HTR-8/SVneo trophoblast cells were evaluated using CCK-8 assay for proliferation, wound-healing assay (500 μm standardized scratch) for migration, and Matrigel Transwell assay for invasion. 3.Omics analysis and validation: High-throughput sequencing (Illumina NovaSeq6000, 2×150bp) was performed to identify differentially expressed RNAs. The ceRNA network was constructed using TargetScan and StarBase databases. Molecular interactions were validated by dual-luciferase reporter assay in 293T cells. Results: 1.Functional characterization of exosomes: PE placental exosomes significantly inhibited trophoblast proliferation (62.3% vs control, p<0.001), migration (34.2% vs 82.1% wound closure, p<0.01), and invasion (57.8% reduction in transmigration, p<0.001), while normal exosomes promoted these functions (p<0.05). 2.Molecular profiling: RNA sequencing identified 794 differentially expressed lncRNAs (426 up/368 down), 273 mRNAs (145 up/128 down), and 28 miRNAs (11 up/17 down). Notably, LINC00923 (0.41±0.07 vs 1.00±0.12) and CACNG7 (0.38±0.09 vs 1.00±0.15) were downregulated, while miR-203a-3p was upregulated 3.5-fold (p<0.01). 3.ceRNA mechanism validation: Dual-luciferase assays confirmed that miR-203a-3p directly binds to LINC00923 (68.4% reduction in luciferase activity, p<0.01) and CACNG7 3'UTR (p<0.05). LINC00923 overexpression rescued miR-203a-3p-mediated suppression of CACNG7 (p<0.01). Functional rescue experiments demonstrated that LINC00923 supplementation restored trophoblast invasion capacity to 83.6% of control levels (p<0.001). Conclusion: This study reveals a novel mechanism by which PE placental exosomes regulate trophoblast function through the LINC00923/miR-203a-3p/CACNG7 axis. LINC00923 functions as a competing endogenous RNA to sequester miR-203a-3p, thereby alleviating its suppression of CACNG7 and improving trophoblast proliferation and invasion. The decreased LINC00923 expression in PE exosomes disrupts this regulatory balance, contributing to trophoblast dysfunction. These findings not only advance our understanding of PE pathogenesis but also provide a foundation for developing exosomal lncRNA-based diagnostic markers and targeted therapies.