Perfluorooctanoic acid-associated complement factor B upregulation and atrial fibrillation-related molecular alterations: integrated network toxicology, Mendelian randomization, molecular dynamics, and HL-1 cell analyses.

Background: Perfluorooctanoic acid (PFOA) is a persistent environmental pollutant associated with cardiovascular dysfunction, but the molecular links between PFOA exposure and atrial fibrillation (AF) remain unclear. We aimed to prioritize a candidate mediator connecting PFOA with AF and examine its associated molecular effects in atrial cardiomyocytes. Methods: PFOA-associated or computationally predicted genes from CTD, STITCH, and SwissTargetPrediction were integrated with AF-associated genes. Complement factor B (CFB) was evaluated using exploratory Mendelian randomization, public single-cell analysis, protein-interaction and enrichment analyses, molecular docking, a single 100-ns molecular dynamics trajectory, and HL-1 cell experiments. Cells were exposed to 25 μM PFOA for 48 h with or without CFB silencing, followed by qRT-PCR, Western blotting, immunofluorescence, and CCK-8 assays. Results: CFB was the only shared candidate between the integrated PFOA-related target set and the filtered AF-associated gene set. Genetically predicted plasma CFB levels were positively associated with AF risk (odds ratio = 1.109, 95% confidence interval: 1.021-1.205; FDR-adjusted Conclusion: These findings prioritize CFB as a candidate molecule potentially associated with PFOA exposure and AF-related molecular alterations. They do not establish direct PFOA-CFB binding, functional complement activation, causality, electrical remodeling, or a functional AF phenotype.