Interactive effects of Bisphenol F exposure and TLR4 rs4986790 on unexplained miscarriage

BACKGROUND: Unexplained miscarriage (UM) occurs frequently and significantly limits global human reproduction. However, till now, whether environment-gene interactions might interactively regulate UM has not been well characterised. METHODS: We combined epidemiological study using a UM case-control group and in vitro functional assays using mouse model and human trophoblast HTR-8/SVneo cells. The interactions between environmental exposure to Bisphenol F (BPF) and genetic variation in TLR4 rs4986790 (A896G) were explored. Trophoblast cell migration and invasion (key functions for healthy pregnancy), the interactions between TLR4 variants and β2GPI (β-2 glycoprotein I, an inflammatory mediator), and the downstream signalling molecules MMP9 and RAC1 were investigated. FINDINGS: BPF exposure and the TLR4 rs4986790 genotype interactively influence the occurrence of UM and impaired trophoblast cell migration/invasion. Mechanistically, TLR4-A binds more strongly to β2GPI than TLR4-G. BPF exposure further enhances β2GPI-TLR4-A interactions but has a lesser effect on β2GPI-TLR4-G. As a result, BPF more severely suppresses MMP9 and RAC1 protein levels-critical for cell migration/invasion-in TLR4-A cells. INTERPRETATION: Collectively, this study discovers that BPF exposure and TLR4 rs4986790 interactively govern trophoblast cell migration/invasion and UM from epidemiological, functional, and mechanistic perspectives, providing a comprehensive methodology for further investigation of environment-gene interactions in other diseases and a scientific foundation for precise treatment against various human diseases. FUNDING: This work was supported by the Natural Science Foundation of China (NSFC No. 82373602), Shenzhen Medical Research Fund (No. B2303002), Guangdong Basic and Applied Basic Research Foundation (2023B1515120054 and 2023A1515110497), Shenzhen Science and Technology Programme (No. JCYJ20220530144403008, JCYJ20220818103607015, JCYJ20230807111401002, JCYJ20240813180400002, and JCYJ20241202152800001), Hebei Natural Science Foundation (B2024201087), Futian Healthcare Research Project (No. FTWS011 and FTWS2022002).