Bisphenol A potentiates ischemia-reperfusion-induced endothelial and blood-brain barrier dysfunction associated with CX3CL1-CX3CR1 signaling.

Bisphenol A (BPA) is a widely distributed environmental contaminant; however, its potential role in modulating ischemic neurovascular injury remains unclear. We applied an integrative approach combining network toxicology, Mendelian randomization, molecular docking, and single-cell transcriptomics to identify BPA-responsive targets relevant to ischemic stroke. CX3CL1 was prioritized based on network centrality, genetic association with stroke risk, and endothelial enrichment in post-ischemic brain tissue. Functional validation was performed in bEnd.3 brain endothelial cells and an endothelial-astrocyte Transwell blood-brain barrier (BBB) co-culture model subjected to oxygen-glucose deprivation/reoxygenation (OGD/R). Under normoxic conditions, BPA (50 and 100 μM) did not markedly reduce cell viability; however, it significantly aggravated OGD/R-induced injury. BPA increased endothelial apoptosis (10.1% and 21.2% vs. 4.6% under OGD/R alone), elevated CX3CL1 protein expression (1.71- and 2.28-fold vs. control), increased BAX, and reduced Bcl-2 levels. Tight junction proteins were substantially decreased (claudin-5: 0.49 and 0.24; ZO-1: 0.46 and 0.23 relative to control), accompanied by reduced transendothelial electrical resistance and increased FITC-dextran permeability. Pharmacological inhibition of CX3CR1 using AZD8797 (0.5 μM) partially attenuated BPA-exacerbated apoptosis, tight junction loss, and barrier hyperpermeability without significantly altering CX3CL1 expression. Collectively, these findings suggest that BPA potentiates ischemia-reperfusion-associated endothelial and barrier dysfunction, accompanied by changes in CX3CL1-CX3CR1-related signaling, and support a potential role for environmental toxicants as modifiers of ischemic neurovascular vulnerability.